diff -r 000000000000 -r 6474c204b198 dom/workers/WorkerPrivate.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/WorkerPrivate.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,5978 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WorkerPrivate.h"
+
+#include "amIAddonManager.h"
+#include "nsIClassInfo.h"
+#include "nsIContentSecurityPolicy.h"
+#include "nsIConsoleService.h"
+#include "nsIDOMDOMException.h"
+#include "nsIDOMEvent.h"
+#include "nsIDOMFile.h"
+#include "nsIDOMMessageEvent.h"
+#include "nsIDocument.h"
+#include "nsIDocShell.h"
+#include "nsIMemoryReporter.h"
+#include "nsIPermissionManager.h"
+#include "nsIScriptError.h"
+#include "nsIScriptGlobalObject.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsPIDOMWindow.h"
+#include "nsITextToSubURI.h"
+#include "nsIThreadInternal.h"
+#include "nsITimer.h"
+#include "nsIURI.h"
+#include "nsIURL.h"
+#include "nsIXPConnect.h"
+
+#include <algorithm>
+#include "jsfriendapi.h"
+#include "js/OldDebugAPI.h"
+#include "js/MemoryMetrics.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ContentEvents.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/Likely.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/ErrorEvent.h"
+#include "mozilla/dom/ErrorEventBinding.h"
+#include "mozilla/dom/Exceptions.h"
+#include "mozilla/dom/FunctionBinding.h"
+#include "mozilla/dom/ImageData.h"
+#include "mozilla/dom/ImageDataBinding.h"
+#include "mozilla/dom/MessageEvent.h"
+#include "mozilla/dom/MessageEventBinding.h"
+#include "mozilla/dom/MessagePortList.h"
+#include "mozilla/dom/WorkerBinding.h"
+#include "mozilla/Preferences.h"
+#include "nsAlgorithm.h"
+#include "nsContentUtils.h"
+#include "nsCxPusher.h"
+#include "nsError.h"
+#include "nsDOMJSUtils.h"
+#include "nsHostObjectProtocolHandler.h"
+#include "nsJSEnvironment.h"
+#include "nsJSUtils.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsProxyRelease.h"
+#include "nsSandboxFlags.h"
+#include "xpcpublic.h"
+
+#ifdef ANDROID
+#include <android/log.h>
+#endif
+
+#ifdef DEBUG
+#include "nsThreadManager.h"
+#endif
+
+#include "File.h"
+#include "MessagePort.h"
+#include "Navigator.h"
+#include "Principal.h"
+#include "RuntimeService.h"
+#include "ScriptLoader.h"
+#include "SharedWorker.h"
+#include "WorkerFeature.h"
+#include "WorkerRunnable.h"
+#include "WorkerScope.h"
+
+// JS_MaybeGC will run once every second during normal execution.
+#define PERIODIC_GC_TIMER_DELAY_SEC 1
+
+// A shrinking GC will run five seconds after the last event is processed.
+#define IDLE_GC_TIMER_DELAY_SEC 5
+
+#define PREF_WORKERS_ENABLED "dom.workers.enabled"
+
+#ifdef WORKER_LOGGING
+#define LOG(_args) do { printf _args ; fflush(stdout); } while (0)
+#else
+#define LOG(_args) do { } while (0)
+#endif
+
+using namespace mozilla;
+using namespace mozilla::dom;
+USING_WORKERS_NAMESPACE
+
+MOZ_DEFINE_MALLOC_SIZE_OF(JsWorkerMallocSizeOf)
+
+#ifdef DEBUG
+
+BEGIN_WORKERS_NAMESPACE
+
+void
+AssertIsOnMainThread()
+{
+  MOZ_ASSERT(NS_IsMainThread(), "Wrong thread!");
+}
+
+END_WORKERS_NAMESPACE
+
+#endif
+
+namespace {
+
+#ifdef DEBUG
+
+const nsIID kDEBUGWorkerEventTargetIID = {
+  0xccaba3fa, 0x5be2, 0x4de2, { 0xba, 0x87, 0x3b, 0x3b, 0x5b, 0x1d, 0x5, 0xfb }
+};
+
+#endif
+
+template <class T>
+class AutoPtrComparator
+{
+  typedef nsAutoPtr<T> A;
+  typedef T* B;
+
+public:
+  bool Equals(const A& a, const B& b) const {
+    return a && b ? *a == *b : !a && !b ? true : false;
+  }
+  bool LessThan(const A& a, const B& b) const {
+    return a && b ? *a < *b : b ? true : false;
+  }
+};
+
+template <class T>
+inline AutoPtrComparator<T>
+GetAutoPtrComparator(const nsTArray<nsAutoPtr<T> >&)
+{
+  return AutoPtrComparator<T>();
+}
+
+// Specialize this if there's some class that has multiple nsISupports bases.
+template <class T>
+struct ISupportsBaseInfo
+{
+  typedef T ISupportsBase;
+};
+
+template <template <class> class SmartPtr, class T>
+inline void
+SwapToISupportsArray(SmartPtr<T>& aSrc,
+                     nsTArray<nsCOMPtr<nsISupports> >& aDest)
+{
+  nsCOMPtr<nsISupports>* dest = aDest.AppendElement();
+
+  T* raw = nullptr;
+  aSrc.swap(raw);
+
+  nsISupports* rawSupports =
+    static_cast<typename ISupportsBaseInfo<T>::ISupportsBase*>(raw);
+  dest->swap(rawSupports);
+}
+
+// This class is used to wrap any runnables that the worker receives via the
+// nsIEventTarget::Dispatch() method (either from NS_DispatchToCurrentThread or
+// from the worker's EventTarget).
+class ExternalRunnableWrapper MOZ_FINAL : public WorkerRunnable
+{
+  nsCOMPtr<nsICancelableRunnable> mWrappedRunnable;
+
+public:
+  ExternalRunnableWrapper(WorkerPrivate* aWorkerPrivate,
+                          nsICancelableRunnable* aWrappedRunnable)
+  : WorkerRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mWrappedRunnable(aWrappedRunnable)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(aWrappedRunnable);
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+private:
+  ~ExternalRunnableWrapper()
+  { }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    nsresult rv = mWrappedRunnable->Run();
+    if (NS_FAILED(rv)) {
+      if (!JS_IsExceptionPending(aCx)) {
+        Throw(aCx, rv);
+      }
+      return false;
+    }
+    return true;
+  }
+
+  NS_IMETHOD
+  Cancel() MOZ_OVERRIDE
+  {
+    nsresult rv = mWrappedRunnable->Cancel();
+    nsresult rv2 = WorkerRunnable::Cancel();
+    return NS_FAILED(rv) ? rv : rv2;
+  }
+};
+
+struct WindowAction
+{
+  nsPIDOMWindow* mWindow;
+  JSContext* mJSContext;
+  bool mDefaultAction;
+
+  WindowAction(nsPIDOMWindow* aWindow, JSContext* aJSContext)
+  : mWindow(aWindow), mJSContext(aJSContext), mDefaultAction(true)
+  {
+    MOZ_ASSERT(aJSContext);
+  }
+
+  WindowAction(nsPIDOMWindow* aWindow)
+  : mWindow(aWindow), mJSContext(nullptr), mDefaultAction(true)
+  { }
+
+  bool
+  operator==(const WindowAction& aOther) const
+  {
+    return mWindow == aOther.mWindow;
+  }
+};
+
+void
+LogErrorToConsole(const nsAString& aMessage,
+                  const nsAString& aFilename,
+                  const nsAString& aLine,
+                  uint32_t aLineNumber,
+                  uint32_t aColumnNumber,
+                  uint32_t aFlags,
+                  uint64_t aInnerWindowId)
+{
+  AssertIsOnMainThread();
+
+  nsCOMPtr<nsIScriptError> scriptError =
+    do_CreateInstance(NS_SCRIPTERROR_CONTRACTID);
+  NS_WARN_IF_FALSE(scriptError, "Failed to create script error!");
+
+  if (scriptError) {
+    if (NS_FAILED(scriptError->InitWithWindowID(aMessage, aFilename, aLine,
+                                                aLineNumber, aColumnNumber,
+                                                aFlags, "Web Worker",
+                                                aInnerWindowId))) {
+      NS_WARNING("Failed to init script error!");
+      scriptError = nullptr;
+    }
+  }
+
+  nsCOMPtr<nsIConsoleService> consoleService =
+    do_GetService(NS_CONSOLESERVICE_CONTRACTID);
+  NS_WARN_IF_FALSE(consoleService, "Failed to get console service!");
+
+  if (consoleService) {
+    if (scriptError) {
+      if (NS_SUCCEEDED(consoleService->LogMessage(scriptError))) {
+        return;
+      }
+      NS_WARNING("LogMessage failed!");
+    } else if (NS_SUCCEEDED(consoleService->LogStringMessage(
+                                                    aMessage.BeginReading()))) {
+      return;
+    }
+    NS_WARNING("LogStringMessage failed!");
+  }
+
+  NS_ConvertUTF16toUTF8 msg(aMessage);
+  NS_ConvertUTF16toUTF8 filename(aFilename);
+
+  static const char kErrorString[] = "JS error in Web Worker: %s [%s:%u]";
+
+#ifdef ANDROID
+  __android_log_print(ANDROID_LOG_INFO, "Gecko", kErrorString, msg.get(),
+                      filename.get(), aLineNumber);
+#endif
+
+  fprintf(stderr, kErrorString, msg.get(), filename.get(), aLineNumber);
+  fflush(stderr);
+}
+
+struct WorkerStructuredCloneCallbacks
+{
+  static JSObject*
+  Read(JSContext* aCx, JSStructuredCloneReader* aReader, uint32_t aTag,
+       uint32_t aData, void* aClosure)
+  {
+    // See if object is a nsIDOMFile pointer.
+    if (aTag == DOMWORKER_SCTAG_FILE) {
+      MOZ_ASSERT(!aData);
+
+      nsIDOMFile* file;
+      if (JS_ReadBytes(aReader, &file, sizeof(file))) {
+        MOZ_ASSERT(file);
+
+#ifdef DEBUG
+        {
+          // File should not be mutable.
+          nsCOMPtr<nsIMutable> mutableFile = do_QueryInterface(file);
+          bool isMutable;
+          NS_ASSERTION(NS_SUCCEEDED(mutableFile->GetMutable(&isMutable)) &&
+                       !isMutable,
+                       "Only immutable file should be passed to worker");
+        }
+#endif
+
+        // nsIDOMFiles should be threadsafe, thus we will use the same instance
+        // in the worker.
+        JSObject* jsFile = file::CreateFile(aCx, file);
+        return jsFile;
+      }
+    }
+    // See if object is a nsIDOMBlob pointer.
+    else if (aTag == DOMWORKER_SCTAG_BLOB) {
+      MOZ_ASSERT(!aData);
+
+      nsIDOMBlob* blob;
+      if (JS_ReadBytes(aReader, &blob, sizeof(blob))) {
+        MOZ_ASSERT(blob);
+
+#ifdef DEBUG
+        {
+          // Blob should not be mutable.
+          nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(blob);
+          bool isMutable;
+          NS_ASSERTION(NS_SUCCEEDED(mutableBlob->GetMutable(&isMutable)) &&
+                       !isMutable,
+                       "Only immutable blob should be passed to worker");
+        }
+#endif
+
+        // nsIDOMBlob should be threadsafe, thus we will use the same instance
+        // in the worker.
+        JSObject* jsBlob = file::CreateBlob(aCx, blob);
+        return jsBlob;
+      }
+    }
+    // See if the object is an ImageData.
+    else if (aTag == SCTAG_DOM_IMAGEDATA) {
+      MOZ_ASSERT(!aData);
+
+      // Read the information out of the stream.
+      uint32_t width, height;
+      JS::Rooted<JS::Value> dataArray(aCx);
+      if (!JS_ReadUint32Pair(aReader, &width, &height) ||
+          !JS_ReadTypedArray(aReader, &dataArray))
+      {
+        return nullptr;
+      }
+      MOZ_ASSERT(dataArray.isObject());
+
+      JS::Rooted<JSObject*> result(aCx);
+      {
+        // Construct the ImageData.
+        nsRefPtr<ImageData> imageData = new ImageData(width, height,
+                                                      dataArray.toObject());
+        // Wrap it in a JS::Value, protected from a moving GC during ~nsRefPtr.
+        result = imageData->WrapObject(aCx);
+      }
+      return result;
+    }
+
+    Error(aCx, 0);
+    return nullptr;
+  }
+
+  static bool
+  Write(JSContext* aCx, JSStructuredCloneWriter* aWriter,
+        JS::Handle<JSObject*> aObj, void* aClosure)
+  {
+    NS_ASSERTION(aClosure, "Null pointer!");
+
+    // We'll stash any nsISupports pointers that need to be AddRef'd here.
+    nsTArray<nsCOMPtr<nsISupports> >* clonedObjects =
+      static_cast<nsTArray<nsCOMPtr<nsISupports> >*>(aClosure);
+
+    // See if this is a File object.
+    {
+      nsIDOMFile* file = file::GetDOMFileFromJSObject(aObj);
+      if (file) {
+        if (JS_WriteUint32Pair(aWriter, DOMWORKER_SCTAG_FILE, 0) &&
+            JS_WriteBytes(aWriter, &file, sizeof(file))) {
+          clonedObjects->AppendElement(file);
+          return true;
+        }
+      }
+    }
+
+    // See if this is a Blob object.
+    {
+      nsIDOMBlob* blob = file::GetDOMBlobFromJSObject(aObj);
+      if (blob) {
+        nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(blob);
+        if (mutableBlob && NS_SUCCEEDED(mutableBlob->SetMutable(false)) &&
+            JS_WriteUint32Pair(aWriter, DOMWORKER_SCTAG_BLOB, 0) &&
+            JS_WriteBytes(aWriter, &blob, sizeof(blob))) {
+          clonedObjects->AppendElement(blob);
+          return true;
+        }
+      }
+    }
+
+    // See if this is an ImageData object.
+    {
+      ImageData* imageData = nullptr;
+      if (NS_SUCCEEDED(UNWRAP_OBJECT(ImageData, aObj, imageData))) {
+        // Prepare the ImageData internals.
+        uint32_t width = imageData->Width();
+        uint32_t height = imageData->Height();
+        JS::Rooted<JSObject*> dataArray(aCx, imageData->GetDataObject());
+
+        // Write the internals to the stream.
+        JSAutoCompartment ac(aCx, dataArray);
+        JS::Rooted<JS::Value> arrayValue(aCx, JS::ObjectValue(*dataArray));
+        return JS_WriteUint32Pair(aWriter, SCTAG_DOM_IMAGEDATA, 0) &&
+               JS_WriteUint32Pair(aWriter, width, height) &&
+               JS_WriteTypedArray(aWriter, arrayValue);
+      }
+    }
+
+    Error(aCx, 0);
+    return false;
+  }
+
+  static void
+  Error(JSContext* aCx, uint32_t /* aErrorId */)
+  {
+    Throw(aCx, NS_ERROR_DOM_DATA_CLONE_ERR);
+  }
+};
+
+JSStructuredCloneCallbacks gWorkerStructuredCloneCallbacks = {
+  WorkerStructuredCloneCallbacks::Read,
+  WorkerStructuredCloneCallbacks::Write,
+  WorkerStructuredCloneCallbacks::Error,
+  nullptr,
+  nullptr,
+  nullptr
+};
+
+struct MainThreadWorkerStructuredCloneCallbacks
+{
+  static JSObject*
+  Read(JSContext* aCx, JSStructuredCloneReader* aReader, uint32_t aTag,
+       uint32_t aData, void* aClosure)
+  {
+    AssertIsOnMainThread();
+
+    // See if object is a nsIDOMFile pointer.
+    if (aTag == DOMWORKER_SCTAG_FILE) {
+      MOZ_ASSERT(!aData);
+
+      nsIDOMFile* file;
+      if (JS_ReadBytes(aReader, &file, sizeof(file))) {
+        MOZ_ASSERT(file);
+
+#ifdef DEBUG
+        {
+          // File should not be mutable.
+          nsCOMPtr<nsIMutable> mutableFile = do_QueryInterface(file);
+          bool isMutable;
+          NS_ASSERTION(NS_SUCCEEDED(mutableFile->GetMutable(&isMutable)) &&
+                       !isMutable,
+                       "Only immutable file should be passed to worker");
+        }
+#endif
+
+        // nsIDOMFiles should be threadsafe, thus we will use the same instance
+        // on the main thread.
+        JS::Rooted<JS::Value> wrappedFile(aCx);
+        nsresult rv = nsContentUtils::WrapNative(aCx, file,
+                                                 &NS_GET_IID(nsIDOMFile),
+                                                 &wrappedFile);
+        if (NS_FAILED(rv)) {
+          Error(aCx, nsIDOMDOMException::DATA_CLONE_ERR);
+          return nullptr;
+        }
+
+        return &wrappedFile.toObject();
+      }
+    }
+    // See if object is a nsIDOMBlob pointer.
+    else if (aTag == DOMWORKER_SCTAG_BLOB) {
+      MOZ_ASSERT(!aData);
+
+      nsIDOMBlob* blob;
+      if (JS_ReadBytes(aReader, &blob, sizeof(blob))) {
+        MOZ_ASSERT(blob);
+
+#ifdef DEBUG
+        {
+          // Blob should not be mutable.
+          nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(blob);
+          bool isMutable;
+          NS_ASSERTION(NS_SUCCEEDED(mutableBlob->GetMutable(&isMutable)) &&
+                       !isMutable,
+                       "Only immutable blob should be passed to worker");
+        }
+#endif
+
+        // nsIDOMBlobs should be threadsafe, thus we will use the same instance
+        // on the main thread.
+        JS::Rooted<JS::Value> wrappedBlob(aCx);
+        nsresult rv = nsContentUtils::WrapNative(aCx, blob,
+                                                 &NS_GET_IID(nsIDOMBlob),
+                                                 &wrappedBlob);
+        if (NS_FAILED(rv)) {
+          Error(aCx, nsIDOMDOMException::DATA_CLONE_ERR);
+          return nullptr;
+        }
+
+        return &wrappedBlob.toObject();
+      }
+    }
+
+    JS_ClearPendingException(aCx);
+    return NS_DOMReadStructuredClone(aCx, aReader, aTag, aData, nullptr);
+  }
+
+  static bool
+  Write(JSContext* aCx, JSStructuredCloneWriter* aWriter,
+        JS::Handle<JSObject*> aObj, void* aClosure)
+  {
+    AssertIsOnMainThread();
+
+    NS_ASSERTION(aClosure, "Null pointer!");
+
+    // We'll stash any nsISupports pointers that need to be AddRef'd here.
+    nsTArray<nsCOMPtr<nsISupports> >* clonedObjects =
+      static_cast<nsTArray<nsCOMPtr<nsISupports> >*>(aClosure);
+
+    // See if this is a wrapped native.
+    nsCOMPtr<nsIXPConnectWrappedNative> wrappedNative;
+    nsContentUtils::XPConnect()->
+      GetWrappedNativeOfJSObject(aCx, aObj, getter_AddRefs(wrappedNative));
+
+    if (wrappedNative) {
+      // Get the raw nsISupports out of it.
+      nsISupports* wrappedObject = wrappedNative->Native();
+      NS_ASSERTION(wrappedObject, "Null pointer?!");
+
+      nsISupports* ccISupports = nullptr;
+      wrappedObject->QueryInterface(NS_GET_IID(nsCycleCollectionISupports),
+                                    reinterpret_cast<void**>(&ccISupports));
+      if (ccISupports) {
+        NS_WARNING("Cycle collected objects are not supported!");
+      }
+      else {
+        // See if the wrapped native is a nsIDOMFile.
+        nsCOMPtr<nsIDOMFile> file = do_QueryInterface(wrappedObject);
+        if (file) {
+          nsCOMPtr<nsIMutable> mutableFile = do_QueryInterface(file);
+          if (mutableFile && NS_SUCCEEDED(mutableFile->SetMutable(false))) {
+            nsIDOMFile* filePtr = file;
+            if (JS_WriteUint32Pair(aWriter, DOMWORKER_SCTAG_FILE, 0) &&
+                JS_WriteBytes(aWriter, &filePtr, sizeof(filePtr))) {
+              clonedObjects->AppendElement(file);
+              return true;
+            }
+          }
+        }
+
+        // See if the wrapped native is a nsIDOMBlob.
+        nsCOMPtr<nsIDOMBlob> blob = do_QueryInterface(wrappedObject);
+        if (blob) {
+          nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(blob);
+          if (mutableBlob && NS_SUCCEEDED(mutableBlob->SetMutable(false))) {
+            nsIDOMBlob* blobPtr = blob;
+            if (JS_WriteUint32Pair(aWriter, DOMWORKER_SCTAG_BLOB, 0) &&
+                JS_WriteBytes(aWriter, &blobPtr, sizeof(blobPtr))) {
+              clonedObjects->AppendElement(blob);
+              return true;
+            }
+          }
+        }
+      }
+    }
+
+    JS_ClearPendingException(aCx);
+    return NS_DOMWriteStructuredClone(aCx, aWriter, aObj, nullptr);
+  }
+
+  static void
+  Error(JSContext* aCx, uint32_t aErrorId)
+  {
+    AssertIsOnMainThread();
+
+    NS_DOMStructuredCloneError(aCx, aErrorId);
+  }
+};
+
+JSStructuredCloneCallbacks gMainThreadWorkerStructuredCloneCallbacks = {
+  MainThreadWorkerStructuredCloneCallbacks::Read,
+  MainThreadWorkerStructuredCloneCallbacks::Write,
+  MainThreadWorkerStructuredCloneCallbacks::Error,
+  nullptr,
+  nullptr,
+  nullptr
+};
+
+struct ChromeWorkerStructuredCloneCallbacks
+{
+  static JSObject*
+  Read(JSContext* aCx, JSStructuredCloneReader* aReader, uint32_t aTag,
+       uint32_t aData, void* aClosure)
+  {
+    return WorkerStructuredCloneCallbacks::Read(aCx, aReader, aTag, aData,
+                                                aClosure);
+  }
+
+  static bool
+  Write(JSContext* aCx, JSStructuredCloneWriter* aWriter,
+        JS::Handle<JSObject*> aObj, void* aClosure)
+  {
+    return WorkerStructuredCloneCallbacks::Write(aCx, aWriter, aObj, aClosure);
+  }
+
+  static void
+  Error(JSContext* aCx, uint32_t aErrorId)
+  {
+    return WorkerStructuredCloneCallbacks::Error(aCx, aErrorId);
+  }
+};
+
+JSStructuredCloneCallbacks gChromeWorkerStructuredCloneCallbacks = {
+  ChromeWorkerStructuredCloneCallbacks::Read,
+  ChromeWorkerStructuredCloneCallbacks::Write,
+  ChromeWorkerStructuredCloneCallbacks::Error,
+  nullptr,
+  nullptr,
+  nullptr
+};
+
+struct MainThreadChromeWorkerStructuredCloneCallbacks
+{
+  static JSObject*
+  Read(JSContext* aCx, JSStructuredCloneReader* aReader, uint32_t aTag,
+       uint32_t aData, void* aClosure)
+  {
+    AssertIsOnMainThread();
+
+    JSObject* clone =
+      MainThreadWorkerStructuredCloneCallbacks::Read(aCx, aReader, aTag, aData,
+                                                     aClosure);
+    if (clone) {
+      return clone;
+    }
+
+    clone =
+      ChromeWorkerStructuredCloneCallbacks::Read(aCx, aReader, aTag, aData,
+                                                 aClosure);
+    if (clone) {
+      return clone;
+    }
+
+    JS_ClearPendingException(aCx);
+    return NS_DOMReadStructuredClone(aCx, aReader, aTag, aData, nullptr);
+  }
+
+  static bool
+  Write(JSContext* aCx, JSStructuredCloneWriter* aWriter,
+        JS::Handle<JSObject*> aObj, void* aClosure)
+  {
+    AssertIsOnMainThread();
+
+    if (MainThreadWorkerStructuredCloneCallbacks::Write(aCx, aWriter, aObj,
+                                                        aClosure) ||
+        ChromeWorkerStructuredCloneCallbacks::Write(aCx, aWriter, aObj,
+                                                    aClosure) ||
+        NS_DOMWriteStructuredClone(aCx, aWriter, aObj, nullptr)) {
+      return true;
+    }
+
+    return false;
+  }
+
+  static void
+  Error(JSContext* aCx, uint32_t aErrorId)
+  {
+    AssertIsOnMainThread();
+
+    NS_DOMStructuredCloneError(aCx, aErrorId);
+  }
+};
+
+JSStructuredCloneCallbacks gMainThreadChromeWorkerStructuredCloneCallbacks = {
+  MainThreadChromeWorkerStructuredCloneCallbacks::Read,
+  MainThreadChromeWorkerStructuredCloneCallbacks::Write,
+  MainThreadChromeWorkerStructuredCloneCallbacks::Error,
+  nullptr,
+  nullptr,
+  nullptr
+};
+
+class MainThreadReleaseRunnable MOZ_FINAL : public nsRunnable
+{
+  nsTArray<nsCOMPtr<nsISupports>> mDoomed;
+  nsTArray<nsCString> mHostObjectURIs;
+
+public:
+  MainThreadReleaseRunnable(nsTArray<nsCOMPtr<nsISupports>>& aDoomed,
+                            nsTArray<nsCString>& aHostObjectURIs)
+  {
+    mDoomed.SwapElements(aDoomed);
+    mHostObjectURIs.SwapElements(aHostObjectURIs);
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_IMETHOD
+  Run() MOZ_OVERRIDE
+  {
+    mDoomed.Clear();
+
+    for (uint32_t index = 0; index < mHostObjectURIs.Length(); index++) {
+      nsHostObjectProtocolHandler::RemoveDataEntry(mHostObjectURIs[index]);
+    }
+
+    return NS_OK;
+  }
+
+private:
+  ~MainThreadReleaseRunnable()
+  { }
+};
+
+class WorkerFinishedRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  WorkerPrivate* mFinishedWorker;
+
+public:
+  WorkerFinishedRunnable(WorkerPrivate* aWorkerPrivate,
+                         WorkerPrivate* aFinishedWorker)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mFinishedWorker(aFinishedWorker)
+  { }
+
+private:
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // Silence bad assertions.
+    return true;
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    // Silence bad assertions.
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    nsTArray<nsCOMPtr<nsISupports>> doomed;
+    mFinishedWorker->ForgetMainThreadObjects(doomed);
+
+    nsTArray<nsCString> hostObjectURIs;
+    mFinishedWorker->StealHostObjectURIs(hostObjectURIs);
+
+    nsRefPtr<MainThreadReleaseRunnable> runnable =
+      new MainThreadReleaseRunnable(doomed, hostObjectURIs);
+    if (NS_FAILED(NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL))) {
+      NS_WARNING("Failed to dispatch, going to leak!");
+    }
+
+    RuntimeService* runtime = RuntimeService::GetService();
+    NS_ASSERTION(runtime, "This should never be null!");
+
+    runtime->UnregisterWorker(aCx, mFinishedWorker);
+
+    mFinishedWorker->ClearSelfRef();
+    return true;
+  }
+};
+
+class TopLevelWorkerFinishedRunnable MOZ_FINAL : public nsRunnable
+{
+  WorkerPrivate* mFinishedWorker;
+
+public:
+  TopLevelWorkerFinishedRunnable(WorkerPrivate* aFinishedWorker)
+  : mFinishedWorker(aFinishedWorker)
+  {
+    aFinishedWorker->AssertIsOnWorkerThread();
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+private:
+  NS_IMETHOD
+  Run() MOZ_OVERRIDE
+  {
+    AssertIsOnMainThread();
+
+    RuntimeService* runtime = RuntimeService::GetService();
+    MOZ_ASSERT(runtime);
+
+    AutoSafeJSContext cx;
+    JSAutoRequest ar(cx);
+
+    runtime->UnregisterWorker(cx, mFinishedWorker);
+
+    nsTArray<nsCOMPtr<nsISupports> > doomed;
+    mFinishedWorker->ForgetMainThreadObjects(doomed);
+
+    nsTArray<nsCString> hostObjectURIs;
+    mFinishedWorker->StealHostObjectURIs(hostObjectURIs);
+
+    nsRefPtr<MainThreadReleaseRunnable> runnable =
+      new MainThreadReleaseRunnable(doomed, hostObjectURIs);
+    if (NS_FAILED(NS_DispatchToCurrentThread(runnable))) {
+      NS_WARNING("Failed to dispatch, going to leak!");
+    }
+
+    mFinishedWorker->ClearSelfRef();
+    return NS_OK;
+  }
+};
+
+class ModifyBusyCountRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  bool mIncrease;
+
+public:
+  ModifyBusyCountRunnable(WorkerPrivate* aWorkerPrivate, bool aIncrease)
+  : WorkerControlRunnable(aWorkerPrivate, ParentThreadUnchangedBusyCount),
+    mIncrease(aIncrease)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    return aWorkerPrivate->ModifyBusyCount(aCx, mIncrease);
+  }
+
+  virtual void
+  PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate, bool aRunResult)
+          MOZ_OVERRIDE
+  {
+    if (mIncrease) {
+      WorkerControlRunnable::PostRun(aCx, aWorkerPrivate, aRunResult);
+      return;
+    }
+    // Don't do anything here as it's possible that aWorkerPrivate has been
+    // deleted.
+  }
+};
+
+class CompileScriptRunnable MOZ_FINAL : public WorkerRunnable
+{
+public:
+  CompileScriptRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerRunnable(aWorkerPrivate, WorkerThreadModifyBusyCount)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    JS::Rooted<JSObject*> global(aCx,
+      aWorkerPrivate->CreateGlobalScope(aCx));
+    if (!global) {
+      NS_WARNING("Failed to make global!");
+      return false;
+    }
+
+    JSAutoCompartment ac(aCx, global);
+    return scriptloader::LoadWorkerScript(aCx);
+  }
+};
+
+class CloseEventRunnable MOZ_FINAL : public WorkerRunnable
+{
+public:
+  CloseEventRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+  { }
+
+private:
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    MOZ_ASSUME_UNREACHABLE("Don't call Dispatch() on CloseEventRunnable!");
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    MOZ_ASSUME_UNREACHABLE("Don't call Dispatch() on CloseEventRunnable!");
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    JS::Rooted<JSObject*> target(aCx, JS::CurrentGlobalOrNull(aCx));
+    NS_ASSERTION(target, "This must never be null!");
+
+    aWorkerPrivate->CloseHandlerStarted();
+
+    WorkerGlobalScope* globalScope = aWorkerPrivate->GlobalScope();
+
+    nsCOMPtr<nsIDOMEvent> event;
+    nsresult rv =
+      NS_NewDOMEvent(getter_AddRefs(event), globalScope, nullptr, nullptr);
+    if (NS_FAILED(rv)) {
+      Throw(aCx, rv);
+      return false;
+    }
+
+    rv = event->InitEvent(NS_LITERAL_STRING("close"), false, false);
+    if (NS_FAILED(rv)) {
+      Throw(aCx, rv);
+      return false;
+    }
+
+    event->SetTrusted(true);
+
+    globalScope->DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+
+    return true;
+  }
+
+  virtual void
+  PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate, bool aRunResult)
+          MOZ_OVERRIDE
+  {
+    // Report errors.
+    WorkerRunnable::PostRun(aCx, aWorkerPrivate, aRunResult);
+
+    // Match the busy count increase from NotifyRunnable.
+    if (!aWorkerPrivate->ModifyBusyCountFromWorker(aCx, false)) {
+      JS_ReportPendingException(aCx);
+    }
+
+    aWorkerPrivate->CloseHandlerFinished();
+  }
+};
+
+class MessageEventRunnable MOZ_FINAL : public WorkerRunnable
+{
+  JSAutoStructuredCloneBuffer mBuffer;
+  nsTArray<nsCOMPtr<nsISupports> > mClonedObjects;
+  uint64_t mMessagePortSerial;
+  bool mToMessagePort;
+
+public:
+  MessageEventRunnable(WorkerPrivate* aWorkerPrivate,
+                       TargetAndBusyBehavior aBehavior,
+                       JSAutoStructuredCloneBuffer&& aData,
+                       nsTArray<nsCOMPtr<nsISupports> >& aClonedObjects,
+                       bool aToMessagePort, uint64_t aMessagePortSerial)
+  : WorkerRunnable(aWorkerPrivate, aBehavior)
+  , mBuffer(Move(aData))
+  , mMessagePortSerial(aMessagePortSerial)
+  , mToMessagePort(aToMessagePort)
+  {
+    mClonedObjects.SwapElements(aClonedObjects);
+  }
+
+  bool
+  DispatchDOMEvent(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+                   DOMEventTargetHelper* aTarget, bool aIsMainThread)
+  {
+    // Release reference to objects that were AddRef'd for
+    // cloning into worker when array goes out of scope.
+    nsTArray<nsCOMPtr<nsISupports>> clonedObjects;
+    clonedObjects.SwapElements(mClonedObjects);
+
+    JS::Rooted<JS::Value> messageData(aCx);
+    if (!mBuffer.read(aCx, &messageData,
+                      workers::WorkerStructuredCloneCallbacks(aIsMainThread))) {
+      xpc::Throw(aCx, NS_ERROR_DOM_DATA_CLONE_ERR);
+      return false;
+    }
+
+    nsRefPtr<MessageEvent> event = new MessageEvent(aTarget, nullptr, nullptr);
+    nsresult rv =
+      event->InitMessageEvent(NS_LITERAL_STRING("message"),
+                              false /* non-bubbling */,
+                              true /* cancelable */,
+                              messageData,
+                              EmptyString(),
+                              EmptyString(),
+                              nullptr);
+    if (NS_FAILED(rv)) {
+      xpc::Throw(aCx, rv);
+      return false;
+    }
+
+    event->SetTrusted(true);
+
+    nsCOMPtr<nsIDOMEvent> domEvent = do_QueryObject(event);
+
+    nsEventStatus dummy = nsEventStatus_eIgnore;
+    aTarget->DispatchDOMEvent(nullptr, domEvent, nullptr, &dummy);
+    return true;
+  }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    MOZ_ASSERT_IF(mToMessagePort, aWorkerPrivate->IsSharedWorker());
+
+    if (mBehavior == ParentThreadUnchangedBusyCount) {
+      // Don't fire this event if the JS object has been disconnected from the
+      // private object.
+      if (!aWorkerPrivate->IsAcceptingEvents()) {
+        return true;
+      }
+
+      if (mToMessagePort) {
+        return
+          aWorkerPrivate->DispatchMessageEventToMessagePort(aCx,
+                                                            mMessagePortSerial,
+                                                            Move(mBuffer),
+                                                            mClonedObjects);
+      }
+
+      if (aWorkerPrivate->IsSuspended()) {
+        aWorkerPrivate->QueueRunnable(this);
+        return true;
+      }
+
+      aWorkerPrivate->AssertInnerWindowIsCorrect();
+
+      return DispatchDOMEvent(aCx, aWorkerPrivate, aWorkerPrivate,
+                              !aWorkerPrivate->GetParent());
+    }
+
+    MOZ_ASSERT(aWorkerPrivate == GetWorkerPrivateFromContext(aCx));
+
+    if (mToMessagePort) {
+      nsRefPtr<workers::MessagePort> port =
+        aWorkerPrivate->GetMessagePort(mMessagePortSerial);
+      if (!port) {
+        // Must have been closed already.
+        return true;
+      }
+      return DispatchDOMEvent(aCx, aWorkerPrivate, port, false);
+    }
+
+    return DispatchDOMEvent(aCx, aWorkerPrivate, aWorkerPrivate->GlobalScope(),
+                            false);
+  }
+};
+
+class NotifyRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  Status mStatus;
+
+public:
+  NotifyRunnable(WorkerPrivate* aWorkerPrivate, Status aStatus)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mStatus(aStatus)
+  {
+    MOZ_ASSERT(aStatus == Closing || aStatus == Terminating ||
+               aStatus == Canceling || aStatus == Killing);
+  }
+
+private:
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // Modify here, but not in PostRun! This busy count addition will be matched
+    // by the CloseEventRunnable.
+    return aWorkerPrivate->ModifyBusyCount(aCx, true);
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    if (!aDispatchResult) {
+      // We couldn't dispatch to the worker, which means it's already dead.
+      // Undo the busy count modification.
+      aWorkerPrivate->ModifyBusyCount(aCx, false);
+    }
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    return aWorkerPrivate->NotifyInternal(aCx, mStatus);
+  }
+};
+
+class CloseRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+public:
+  CloseRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerControlRunnable(aWorkerPrivate, ParentThreadUnchangedBusyCount)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // This busy count will be matched by the CloseEventRunnable.
+    return aWorkerPrivate->ModifyBusyCount(aCx, true) &&
+           aWorkerPrivate->Close(aCx);
+  }
+};
+
+class SuspendRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+public:
+  SuspendRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    return aWorkerPrivate->SuspendInternal(aCx);
+  }
+};
+
+class ResumeRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+public:
+  ResumeRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    return aWorkerPrivate->ResumeInternal(aCx);
+  }
+};
+
+class ReportErrorRunnable MOZ_FINAL : public WorkerRunnable
+{
+  nsString mMessage;
+  nsString mFilename;
+  nsString mLine;
+  uint32_t mLineNumber;
+  uint32_t mColumnNumber;
+  uint32_t mFlags;
+  uint32_t mErrorNumber;
+
+public:
+  // aWorkerPrivate is the worker thread we're on (or the main thread, if null)
+  // aTarget is the worker object that we are going to fire an error at
+  // (if any).
+  static bool
+  ReportError(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+              bool aFireAtScope, WorkerPrivate* aTarget,
+              const nsString& aMessage, const nsString& aFilename,
+              const nsString& aLine, uint32_t aLineNumber,
+              uint32_t aColumnNumber, uint32_t aFlags,
+              uint32_t aErrorNumber, uint64_t aInnerWindowId)
+  {
+    if (aWorkerPrivate) {
+      aWorkerPrivate->AssertIsOnWorkerThread();
+    }
+    else {
+      AssertIsOnMainThread();
+    }
+
+    JS::Rooted<JSString*> message(aCx, JS_NewUCStringCopyN(aCx, aMessage.get(),
+                                                           aMessage.Length()));
+    if (!message) {
+      return false;
+    }
+
+    JS::Rooted<JSString*> filename(aCx, JS_NewUCStringCopyN(aCx, aFilename.get(),
+                                                            aFilename.Length()));
+    if (!filename) {
+      return false;
+    }
+
+    // We should not fire error events for warnings but instead make sure that
+    // they show up in the error console.
+    if (!JSREPORT_IS_WARNING(aFlags)) {
+      // First fire an ErrorEvent at the worker.
+      RootedDictionary<ErrorEventInit> init(aCx);
+      init.mMessage = aMessage;
+      init.mFilename = aFilename;
+      init.mLineno = aLineNumber;
+      init.mCancelable = true;
+      init.mBubbles = true;
+
+      if (aTarget) {
+        nsRefPtr<ErrorEvent> event =
+          ErrorEvent::Constructor(aTarget, NS_LITERAL_STRING("error"), init);
+        event->SetTrusted(true);
+
+        nsEventStatus status = nsEventStatus_eIgnore;
+        aTarget->DispatchDOMEvent(nullptr, event, nullptr, &status);
+
+        if (status == nsEventStatus_eConsumeNoDefault) {
+          return true;
+        }
+      }
+
+      // Now fire an event at the global object, but don't do that if the error
+      // code is too much recursion and this is the same script threw the error.
+      if (aFireAtScope && (aTarget || aErrorNumber != JSMSG_OVER_RECURSED)) {
+        JS::Rooted<JSObject*> target(aCx, JS::CurrentGlobalOrNull(aCx));
+        NS_ASSERTION(target, "This should never be null!");
+
+        nsEventStatus status = nsEventStatus_eIgnore;
+        nsIScriptGlobalObject* sgo;
+
+        if (aWorkerPrivate) {
+          WorkerGlobalScope* globalTarget = aWorkerPrivate->GlobalScope();
+          MOZ_ASSERT(target == globalTarget->GetWrapperPreserveColor());
+
+          nsRefPtr<ErrorEvent> event =
+            ErrorEvent::Constructor(aTarget, NS_LITERAL_STRING("error"), init);
+          event->SetTrusted(true);
+
+          nsIDOMEventTarget* target = static_cast<nsIDOMEventTarget*>(globalTarget);
+          if (NS_FAILED(EventDispatcher::DispatchDOMEvent(target, nullptr,
+                                                          event, nullptr,
+                                                          &status))) {
+            NS_WARNING("Failed to dispatch worker thread error event!");
+            status = nsEventStatus_eIgnore;
+          }
+        }
+        else if ((sgo = nsJSUtils::GetStaticScriptGlobal(target))) {
+          MOZ_ASSERT(NS_IsMainThread());
+
+          if (NS_FAILED(sgo->HandleScriptError(init, &status))) {
+            NS_WARNING("Failed to dispatch main thread error event!");
+            status = nsEventStatus_eIgnore;
+          }
+        }
+
+        // Was preventDefault() called?
+        if (status == nsEventStatus_eConsumeNoDefault) {
+          return true;
+        }
+      }
+    }
+
+    // Now fire a runnable to do the same on the parent's thread if we can.
+    if (aWorkerPrivate) {
+      nsRefPtr<ReportErrorRunnable> runnable =
+        new ReportErrorRunnable(aWorkerPrivate, aMessage, aFilename, aLine,
+                                aLineNumber, aColumnNumber, aFlags,
+                                aErrorNumber);
+      return runnable->Dispatch(aCx);
+    }
+
+    // Otherwise log an error to the error console.
+    LogErrorToConsole(aMessage, aFilename, aLine, aLineNumber, aColumnNumber,
+                      aFlags, aInnerWindowId);
+    return true;
+  }
+
+private:
+  ReportErrorRunnable(WorkerPrivate* aWorkerPrivate, const nsString& aMessage,
+                      const nsString& aFilename, const nsString& aLine,
+                      uint32_t aLineNumber, uint32_t aColumnNumber,
+                      uint32_t aFlags, uint32_t aErrorNumber)
+  : WorkerRunnable(aWorkerPrivate, ParentThreadUnchangedBusyCount),
+    mMessage(aMessage), mFilename(aFilename), mLine(aLine),
+    mLineNumber(aLineNumber), mColumnNumber(aColumnNumber), mFlags(aFlags),
+    mErrorNumber(aErrorNumber)
+  { }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->AssertIsOnWorkerThread();
+
+    // Dispatch may fail if the worker was canceled, no need to report that as
+    // an error, so don't call base class PostDispatch.
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // Don't fire this event if the JS object has been disconnected from the
+    // private object.
+    if (!aWorkerPrivate->IsAcceptingEvents()) {
+      return true;
+    }
+
+    JS::Rooted<JSObject*> target(aCx, aWorkerPrivate->GetWrapper());
+
+    uint64_t innerWindowId;
+    bool fireAtScope = true;
+
+    WorkerPrivate* parent = aWorkerPrivate->GetParent();
+    if (parent) {
+      innerWindowId = 0;
+    }
+    else {
+      AssertIsOnMainThread();
+
+      if (aWorkerPrivate->IsSuspended()) {
+        aWorkerPrivate->QueueRunnable(this);
+        return true;
+      }
+
+      if (aWorkerPrivate->IsSharedWorker()) {
+        aWorkerPrivate->BroadcastErrorToSharedWorkers(aCx, mMessage, mFilename,
+                                                      mLine, mLineNumber,
+                                                      mColumnNumber, mFlags);
+        return true;
+      }
+
+      aWorkerPrivate->AssertInnerWindowIsCorrect();
+
+      innerWindowId = aWorkerPrivate->GetInnerWindowId();
+    }
+
+    return ReportError(aCx, parent, fireAtScope, aWorkerPrivate, mMessage,
+                       mFilename, mLine, mLineNumber, mColumnNumber, mFlags,
+                       mErrorNumber, innerWindowId);
+  }
+};
+
+class TimerRunnable MOZ_FINAL : public WorkerRunnable
+{
+public:
+  TimerRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+  { }
+
+private:
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // Silence bad assertions.
+    return true;
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    // Silence bad assertions.
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    return aWorkerPrivate->RunExpiredTimeouts(aCx);
+  }
+};
+
+void
+DummyCallback(nsITimer* aTimer, void* aClosure)
+{
+  // Nothing!
+}
+
+class TimerThreadEventTarget MOZ_FINAL : public nsIEventTarget
+{
+  WorkerPrivate* mWorkerPrivate;
+  nsRefPtr<WorkerRunnable> mWorkerRunnable;
+
+public:
+  TimerThreadEventTarget(WorkerPrivate* aWorkerPrivate,
+                         WorkerRunnable* aWorkerRunnable)
+  : mWorkerPrivate(aWorkerPrivate), mWorkerRunnable(aWorkerRunnable)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(aWorkerRunnable);
+  }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+protected:
+  NS_IMETHOD
+  Dispatch(nsIRunnable* aRunnable, uint32_t aFlags) MOZ_OVERRIDE
+  {
+    // This should only happen on the timer thread.
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(aFlags == nsIEventTarget::DISPATCH_NORMAL);
+
+    nsRefPtr<TimerThreadEventTarget> kungFuDeathGrip = this;
+
+    // Run the runnable we're given now (should just call DummyCallback()),
+    // otherwise the timer thread will leak it...  If we run this after
+    // dispatch running the event can race against resetting the timer.
+    aRunnable->Run();
+
+    // This can fail if we're racing to terminate or cancel, should be handled
+    // by the terminate or cancel code.
+    mWorkerRunnable->Dispatch(nullptr);
+
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  IsOnCurrentThread(bool* aIsOnCurrentThread) MOZ_OVERRIDE
+  {
+    MOZ_ASSERT(aIsOnCurrentThread);
+
+    nsresult rv = mWorkerPrivate->IsOnCurrentThread(aIsOnCurrentThread);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    return NS_OK;
+  }
+};
+
+class KillCloseEventRunnable MOZ_FINAL : public WorkerRunnable
+{
+  nsCOMPtr<nsITimer> mTimer;
+
+  class KillScriptRunnable MOZ_FINAL : public WorkerControlRunnable
+  {
+  public:
+    KillScriptRunnable(WorkerPrivate* aWorkerPrivate)
+    : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+    { }
+
+  private:
+    virtual bool
+    PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+    {
+      // Silence bad assertions, this is dispatched from the timer thread.
+      return true;
+    }
+
+    virtual void
+    PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+                 bool aDispatchResult) MOZ_OVERRIDE
+    {
+      // Silence bad assertions, this is dispatched from the timer thread.
+    }
+
+    virtual bool
+    WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+    {
+      // Kill running script.
+      return false;
+    }
+  };
+
+public:
+  KillCloseEventRunnable(WorkerPrivate* aWorkerPrivate)
+  : WorkerRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount)
+  { }
+
+  bool
+  SetTimeout(JSContext* aCx, uint32_t aDelayMS)
+  {
+    nsCOMPtr<nsITimer> timer = do_CreateInstance(NS_TIMER_CONTRACTID);
+    if (!timer) {
+      JS_ReportError(aCx, "Failed to create timer!");
+      return false;
+    }
+
+    nsRefPtr<KillScriptRunnable> runnable =
+      new KillScriptRunnable(mWorkerPrivate);
+
+    nsRefPtr<TimerThreadEventTarget> target =
+      new TimerThreadEventTarget(mWorkerPrivate, runnable);
+
+    if (NS_FAILED(timer->SetTarget(target))) {
+      JS_ReportError(aCx, "Failed to set timer's target!");
+      return false;
+    }
+
+    if (NS_FAILED(timer->InitWithFuncCallback(DummyCallback, nullptr, aDelayMS,
+                                              nsITimer::TYPE_ONE_SHOT))) {
+      JS_ReportError(aCx, "Failed to start timer!");
+      return false;
+    }
+
+    mTimer.swap(timer);
+    return true;
+  }
+
+private:
+  ~KillCloseEventRunnable()
+  {
+    if (mTimer) {
+      mTimer->Cancel();
+    }
+  }
+
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    MOZ_ASSUME_UNREACHABLE("Don't call Dispatch() on KillCloseEventRunnable!");
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+               bool aDispatchResult) MOZ_OVERRIDE
+  {
+    MOZ_ASSUME_UNREACHABLE("Don't call Dispatch() on KillCloseEventRunnable!");
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    if (mTimer) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+    }
+
+    return true;
+  }
+};
+
+class UpdateRuntimeAndContextOptionsRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  JS::RuntimeOptions mRuntimeOptions;
+  JS::ContextOptions mContentCxOptions;
+  JS::ContextOptions mChromeCxOptions;
+
+public:
+  UpdateRuntimeAndContextOptionsRunnable(
+                                    WorkerPrivate* aWorkerPrivate,
+                                    const JS::RuntimeOptions& aRuntimeOptions,
+                                    const JS::ContextOptions& aContentCxOptions,
+                                    const JS::ContextOptions& aChromeCxOptions)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mRuntimeOptions(aRuntimeOptions),
+    mContentCxOptions(aContentCxOptions),
+    mChromeCxOptions(aChromeCxOptions)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->UpdateRuntimeAndContextOptionsInternal(aCx,
+                                                           mRuntimeOptions,
+                                                           mContentCxOptions,
+                                                           mChromeCxOptions);
+    return true;
+  }
+};
+
+class UpdatePreferenceRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  WorkerPreference mPref;
+  bool mValue;
+
+public:
+  UpdatePreferenceRunnable(WorkerPrivate* aWorkerPrivate,
+                           WorkerPreference aPref,
+                           bool aValue)
+    : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+      mPref(aPref),
+      mValue(aValue)
+  { }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->UpdatePreferenceInternal(aCx, mPref, mValue);
+    return true;
+  }
+};
+
+class UpdateJSWorkerMemoryParameterRunnable MOZ_FINAL :
+  public WorkerControlRunnable
+{
+  uint32_t mValue;
+  JSGCParamKey mKey;
+
+public:
+  UpdateJSWorkerMemoryParameterRunnable(WorkerPrivate* aWorkerPrivate,
+                                        JSGCParamKey aKey,
+                                        uint32_t aValue)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mValue(aValue), mKey(aKey)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->UpdateJSWorkerMemoryParameterInternal(aCx, mKey, mValue);
+    return true;
+  }
+};
+
+#ifdef JS_GC_ZEAL
+class UpdateGCZealRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  uint8_t mGCZeal;
+  uint32_t mFrequency;
+
+public:
+  UpdateGCZealRunnable(WorkerPrivate* aWorkerPrivate,
+                       uint8_t aGCZeal,
+                       uint32_t aFrequency)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mGCZeal(aGCZeal), mFrequency(aFrequency)
+  { }
+
+private:
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->UpdateGCZealInternal(aCx, mGCZeal, mFrequency);
+    return true;
+  }
+};
+#endif
+
+class GarbageCollectRunnable MOZ_FINAL : public WorkerControlRunnable
+{
+  bool mShrinking;
+  bool mCollectChildren;
+
+public:
+  GarbageCollectRunnable(WorkerPrivate* aWorkerPrivate, bool aShrinking,
+                         bool aCollectChildren)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mShrinking(aShrinking), mCollectChildren(aCollectChildren)
+  { }
+
+private:
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    // Silence bad assertions, this can be dispatched from either the main
+    // thread or the timer thread..
+    return true;
+  }
+
+  virtual void
+  PostDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
+                bool aDispatchResult) MOZ_OVERRIDE
+  {
+    // Silence bad assertions, this can be dispatched from either the main
+    // thread or the timer thread..
+  }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    aWorkerPrivate->GarbageCollectInternal(aCx, mShrinking, mCollectChildren);
+    return true;
+  }
+};
+
+class CycleCollectRunnable : public WorkerControlRunnable
+{
+  bool mCollectChildren;
+
+public:
+  CycleCollectRunnable(WorkerPrivate* aWorkerPrivate, bool aCollectChildren)
+  : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
+    mCollectChildren(aCollectChildren)
+  { }
+
+  bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+  {
+    aWorkerPrivate->CycleCollectInternal(aCx, mCollectChildren);
+    return true;
+  }
+};
+
+class OfflineStatusChangeRunnable : public WorkerRunnable
+{
+public:
+  OfflineStatusChangeRunnable(WorkerPrivate* aWorkerPrivate, bool aIsOffline)
+    : WorkerRunnable(aWorkerPrivate, WorkerThreadModifyBusyCount),
+      mIsOffline(aIsOffline)
+  {
+  }
+
+  bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+  {
+    aWorkerPrivate->OfflineStatusChangeEventInternal(aCx, mIsOffline);
+    return true;
+  }
+
+private:
+  bool mIsOffline;
+};
+
+class WorkerJSRuntimeStats : public JS::RuntimeStats
+{
+  const nsACString& mRtPath;
+
+public:
+  WorkerJSRuntimeStats(const nsACString& aRtPath)
+  : JS::RuntimeStats(JsWorkerMallocSizeOf), mRtPath(aRtPath)
+  { }
+
+  ~WorkerJSRuntimeStats()
+  {
+    for (size_t i = 0; i != zoneStatsVector.length(); i++) {
+      delete static_cast<xpc::ZoneStatsExtras*>(zoneStatsVector[i].extra);
+    }
+
+    for (size_t i = 0; i != compartmentStatsVector.length(); i++) {
+      delete static_cast<xpc::CompartmentStatsExtras*>(compartmentStatsVector[i].extra);
+    }
+  }
+
+  virtual void
+  initExtraZoneStats(JS::Zone* aZone,
+                     JS::ZoneStats* aZoneStats)
+                     MOZ_OVERRIDE
+  {
+    MOZ_ASSERT(!aZoneStats->extra);
+
+    // ReportJSRuntimeExplicitTreeStats expects that
+    // aZoneStats->extra is a xpc::ZoneStatsExtras pointer.
+    xpc::ZoneStatsExtras* extras = new xpc::ZoneStatsExtras;
+    extras->pathPrefix = mRtPath;
+    extras->pathPrefix += nsPrintfCString("zone(0x%p)/", (void *)aZone);
+    aZoneStats->extra = extras;
+  }
+
+  virtual void
+  initExtraCompartmentStats(JSCompartment* aCompartment,
+                            JS::CompartmentStats* aCompartmentStats)
+                            MOZ_OVERRIDE
+  {
+    MOZ_ASSERT(!aCompartmentStats->extra);
+
+    // ReportJSRuntimeExplicitTreeStats expects that
+    // aCompartmentStats->extra is a xpc::CompartmentStatsExtras pointer.
+    xpc::CompartmentStatsExtras* extras = new xpc::CompartmentStatsExtras;
+
+    // This is the |jsPathPrefix|.  Each worker has exactly two compartments:
+    // one for atoms, and one for everything else.
+    extras->jsPathPrefix.Assign(mRtPath);
+    extras->jsPathPrefix += nsPrintfCString("zone(0x%p)/",
+                                            (void *)js::GetCompartmentZone(aCompartment));
+    extras->jsPathPrefix += js::IsAtomsCompartment(aCompartment)
+                            ? NS_LITERAL_CSTRING("compartment(web-worker-atoms)/")
+                            : NS_LITERAL_CSTRING("compartment(web-worker)/");
+
+    // This should never be used when reporting with workers (hence the "?!").
+    extras->domPathPrefix.AssignLiteral("explicit/workers/?!/");
+
+    aCompartmentStats->extra = extras;
+  }
+};
+
+class MessagePortRunnable MOZ_FINAL : public WorkerRunnable
+{
+  uint64_t mMessagePortSerial;
+  bool mConnect;
+
+public:
+  MessagePortRunnable(WorkerPrivate* aWorkerPrivate,
+                      uint64_t aMessagePortSerial,
+                      bool aConnect)
+  : WorkerRunnable(aWorkerPrivate, aConnect ?
+                                   WorkerThreadModifyBusyCount :
+                                   WorkerThreadUnchangedBusyCount),
+    mMessagePortSerial(aMessagePortSerial), mConnect(aConnect)
+  { }
+
+private:
+  ~MessagePortRunnable()
+  { }
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+  {
+    if (mConnect) {
+      return aWorkerPrivate->ConnectMessagePort(aCx, mMessagePortSerial);
+    }
+
+    aWorkerPrivate->DisconnectMessagePort(mMessagePortSerial);
+    return true;
+  }
+};
+
+#ifdef DEBUG
+
+PRThread*
+PRThreadFromThread(nsIThread* aThread)
+{
+  MOZ_ASSERT(aThread);
+
+  PRThread* result;
+  MOZ_ASSERT(NS_SUCCEEDED(aThread->GetPRThread(&result)));
+  MOZ_ASSERT(result);
+
+  return result;
+}
+
+#endif // DEBUG
+
+} /* anonymous namespace */
+
+NS_IMPL_ISUPPORTS_INHERITED0(MainThreadReleaseRunnable, nsRunnable)
+
+NS_IMPL_ISUPPORTS_INHERITED0(TopLevelWorkerFinishedRunnable, nsRunnable)
+
+NS_IMPL_ISUPPORTS(TimerThreadEventTarget, nsIEventTarget)
+
+template <class Derived>
+class WorkerPrivateParent<Derived>::SynchronizeAndResumeRunnable MOZ_FINAL
+  : public nsRunnable
+{
+  friend class nsRevocableEventPtr<SynchronizeAndResumeRunnable>;
+
+  WorkerPrivate* mWorkerPrivate;
+  nsCOMPtr<nsPIDOMWindow> mWindow;
+  nsCOMPtr<nsIScriptContext> mScriptContext;
+
+public:
+  SynchronizeAndResumeRunnable(WorkerPrivate* aWorkerPrivate,
+                               nsPIDOMWindow* aWindow,
+                               nsIScriptContext* aScriptContext)
+  : mWorkerPrivate(aWorkerPrivate), mWindow(aWindow),
+    mScriptContext(aScriptContext)
+  {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(aWindow);
+    MOZ_ASSERT(!aWorkerPrivate->GetParent());
+  }
+
+private:
+  ~SynchronizeAndResumeRunnable()
+  { }
+
+  NS_IMETHOD
+  Run() MOZ_OVERRIDE
+  {
+    AssertIsOnMainThread();
+
+    if (mWorkerPrivate) {
+      AutoPushJSContext cx(mScriptContext ?
+                           mScriptContext->GetNativeContext() :
+                           nsContentUtils::GetSafeJSContext());
+
+      if (!mWorkerPrivate->Resume(cx, mWindow)) {
+        JS_ReportPendingException(cx);
+      }
+    }
+
+    return NS_OK;
+  }
+
+  void
+  Revoke()
+  {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(mWorkerPrivate);
+    MOZ_ASSERT(mWindow);
+
+    mWorkerPrivate = nullptr;
+    mWindow = nullptr;
+    mScriptContext = nullptr;
+  }
+};
+
+template <class Derived>
+class WorkerPrivateParent<Derived>::EventTarget MOZ_FINAL
+  : public nsIEventTarget
+{
+  // This mutex protects mWorkerPrivate and must be acquired *before* the
+  // WorkerPrivate's mutex whenever they must both be held.
+  mozilla::Mutex mMutex;
+  WorkerPrivate* mWorkerPrivate;
+  nsIEventTarget* mWeakNestedEventTarget;
+  nsCOMPtr<nsIEventTarget> mNestedEventTarget;
+
+public:
+  EventTarget(WorkerPrivate* aWorkerPrivate)
+  : mMutex("WorkerPrivateParent::EventTarget::mMutex"),
+    mWorkerPrivate(aWorkerPrivate), mWeakNestedEventTarget(nullptr)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+  }
+
+  EventTarget(WorkerPrivate* aWorkerPrivate, nsIEventTarget* aNestedEventTarget)
+  : mMutex("WorkerPrivateParent::EventTarget::mMutex"),
+    mWorkerPrivate(aWorkerPrivate), mWeakNestedEventTarget(aNestedEventTarget),
+    mNestedEventTarget(aNestedEventTarget)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(aNestedEventTarget);
+  }
+
+  void
+  Disable()
+  {
+    nsCOMPtr<nsIEventTarget> nestedEventTarget;
+    {
+      MutexAutoLock lock(mMutex);
+
+      MOZ_ASSERT(mWorkerPrivate);
+      mWorkerPrivate = nullptr;
+      mNestedEventTarget.swap(nestedEventTarget);
+    }
+  }
+
+  nsIEventTarget*
+  GetWeakNestedEventTarget() const
+  {
+    MOZ_ASSERT(mWeakNestedEventTarget);
+    return mWeakNestedEventTarget;
+  }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIEVENTTARGET
+
+private:
+  ~EventTarget()
+  { }
+};
+
+struct WorkerPrivate::TimeoutInfo
+{
+  TimeoutInfo()
+  : mTimeoutCallable(JS::UndefinedValue()), mLineNumber(0), mId(0),
+    mIsInterval(false), mCanceled(false)
+  {
+    MOZ_COUNT_CTOR(mozilla::dom::workers::WorkerPrivate::TimeoutInfo);
+  }
+
+  ~TimeoutInfo()
+  {
+    MOZ_COUNT_DTOR(mozilla::dom::workers::WorkerPrivate::TimeoutInfo);
+  }
+
+  bool operator==(const TimeoutInfo& aOther)
+  {
+    return mTargetTime == aOther.mTargetTime;
+  }
+
+  bool operator<(const TimeoutInfo& aOther)
+  {
+    return mTargetTime < aOther.mTargetTime;
+  }
+
+  JS::Heap<JS::Value> mTimeoutCallable;
+  nsString mTimeoutString;
+  nsTArray<JS::Heap<JS::Value> > mExtraArgVals;
+  mozilla::TimeStamp mTargetTime;
+  mozilla::TimeDuration mInterval;
+  nsCString mFilename;
+  uint32_t mLineNumber;
+  int32_t mId;
+  bool mIsInterval;
+  bool mCanceled;
+};
+
+class WorkerPrivate::MemoryReporter MOZ_FINAL : public nsIMemoryReporter
+{
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  friend class WorkerPrivate;
+
+  SharedMutex mMutex;
+  WorkerPrivate* mWorkerPrivate;
+  nsCString mRtPath;
+  bool mAlreadyMappedToAddon;
+
+public:
+  MemoryReporter(WorkerPrivate* aWorkerPrivate)
+  : mMutex(aWorkerPrivate->mMutex), mWorkerPrivate(aWorkerPrivate),
+    mAlreadyMappedToAddon(false)
+  {
+    aWorkerPrivate->AssertIsOnWorkerThread();
+
+    nsCString escapedDomain(aWorkerPrivate->Domain());
+    escapedDomain.ReplaceChar('/', '\\');
+
+    NS_ConvertUTF16toUTF8 escapedURL(aWorkerPrivate->ScriptURL());
+    escapedURL.ReplaceChar('/', '\\');
+
+    nsAutoCString addressString;
+    addressString.AppendPrintf("0x%p", static_cast<void*>(aWorkerPrivate));
+
+    mRtPath = NS_LITERAL_CSTRING("explicit/workers/workers(") +
+              escapedDomain + NS_LITERAL_CSTRING(")/worker(") +
+              escapedURL + NS_LITERAL_CSTRING(", ") + addressString +
+              NS_LITERAL_CSTRING(")/");
+  }
+
+  NS_IMETHOD
+  CollectReports(nsIMemoryReporterCallback* aCallback,
+                 nsISupports* aClosure)
+  {
+    AssertIsOnMainThread();
+
+    // Assumes that WorkerJSRuntimeStats will hold a reference to mRtPath,
+    // and not a copy, as TryToMapAddon() may later modify the string again.
+    WorkerJSRuntimeStats rtStats(mRtPath);
+
+    {
+      MutexAutoLock lock(mMutex);
+
+      TryToMapAddon();
+
+      if (!mWorkerPrivate ||
+          !mWorkerPrivate->BlockAndCollectRuntimeStats(&rtStats)) {
+        // Returning NS_OK here will effectively report 0 memory.
+        return NS_OK;
+      }
+    }
+
+    return xpc::ReportJSRuntimeExplicitTreeStats(rtStats, mRtPath,
+                                                 aCallback, aClosure);
+  }
+
+private:
+  ~MemoryReporter()
+  { }
+
+  void
+  Disable()
+  {
+    // Called from WorkerPrivate::DisableMemoryReporter.
+    mMutex.AssertCurrentThreadOwns();
+
+    NS_ASSERTION(mWorkerPrivate, "Disabled more than once!");
+    mWorkerPrivate = nullptr;
+  }
+
+  // Only call this from the main thread and under mMutex lock.
+  void
+  TryToMapAddon()
+  {
+    AssertIsOnMainThread();
+    mMutex.AssertCurrentThreadOwns();
+
+    if (mAlreadyMappedToAddon || !mWorkerPrivate) {
+      return;
+    }
+
+    nsCOMPtr<nsIURI> scriptURI;
+    if (NS_FAILED(NS_NewURI(getter_AddRefs(scriptURI),
+                            mWorkerPrivate->ScriptURL()))) {
+      return;
+    }
+
+    mAlreadyMappedToAddon = true;
+
+    if (XRE_GetProcessType() != GeckoProcessType_Default) {
+      // Only try to access the service from the main process.
+      return;
+    }
+
+    nsAutoCString addonId;
+    bool ok;
+    nsCOMPtr<amIAddonManager> addonManager =
+      do_GetService("@mozilla.org/addons/integration;1");
+
+    if (!addonManager ||
+        NS_FAILED(addonManager->MapURIToAddonID(scriptURI, addonId, &ok)) ||
+        !ok) {
+      return;
+    }
+
+    static const size_t explicitLength = strlen("explicit/");
+    addonId.Insert(NS_LITERAL_CSTRING("add-ons/"), 0);
+    addonId += "/";
+    mRtPath.Insert(addonId, explicitLength);
+  }
+};
+
+NS_IMPL_ISUPPORTS(WorkerPrivate::MemoryReporter, nsIMemoryReporter)
+
+WorkerPrivate::SyncLoopInfo::SyncLoopInfo(EventTarget* aEventTarget)
+: mEventTarget(aEventTarget), mCompleted(false), mResult(false)
+#ifdef DEBUG
+  , mHasRun(false)
+#endif
+{
+}
+
+// Can't use NS_IMPL_CYCLE_COLLECTION_CLASS(WorkerPrivateParent) because of the
+// templates.
+template <class Derived>
+typename WorkerPrivateParent<Derived>::cycleCollection
+  WorkerPrivateParent<Derived>::_cycleCollectorGlobal =
+    WorkerPrivateParent<Derived>::cycleCollection();
+
+template <class Derived>
+WorkerPrivateParent<Derived>::WorkerPrivateParent(
+                                           JSContext* aCx,
+                                           WorkerPrivate* aParent,
+                                           const nsAString& aScriptURL,
+                                           bool aIsChromeWorker,
+                                           WorkerType aWorkerType,
+                                           const nsACString& aSharedWorkerName,
+                                           LoadInfo& aLoadInfo)
+: mMutex("WorkerPrivateParent Mutex"),
+  mCondVar(mMutex, "WorkerPrivateParent CondVar"),
+  mMemoryReportCondVar(mMutex, "WorkerPrivateParent Memory Report CondVar"),
+  mParent(aParent), mScriptURL(aScriptURL),
+  mSharedWorkerName(aSharedWorkerName), mBusyCount(0), mMessagePortSerial(0),
+  mParentStatus(Pending), mParentSuspended(false),
+  mIsChromeWorker(aIsChromeWorker), mMainThreadObjectsForgotten(false),
+  mWorkerType(aWorkerType),
+  mCreationTimeStamp(TimeStamp::Now())
+{
+  SetIsDOMBinding();
+
+  MOZ_ASSERT_IF(IsSharedWorker(), !aSharedWorkerName.IsVoid() &&
+                                  NS_IsMainThread());
+  MOZ_ASSERT_IF(!IsSharedWorker(), aSharedWorkerName.IsEmpty());
+
+  if (aLoadInfo.mWindow) {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(aLoadInfo.mWindow->IsInnerWindow(),
+               "Should have inner window here!");
+    BindToOwner(aLoadInfo.mWindow);
+  }
+
+  mLoadInfo.StealFrom(aLoadInfo);
+
+  if (aParent) {
+    aParent->AssertIsOnWorkerThread();
+
+    aParent->CopyJSSettings(mJSSettings);
+  }
+  else {
+    AssertIsOnMainThread();
+
+    RuntimeService::GetDefaultJSSettings(mJSSettings);
+  }
+}
+
+template <class Derived>
+WorkerPrivateParent<Derived>::~WorkerPrivateParent()
+{
+  DropJSObjects(this);
+}
+
+template <class Derived>
+JSObject*
+WorkerPrivateParent<Derived>::WrapObject(JSContext* aCx)
+{
+  MOZ_ASSERT(!IsSharedWorker(),
+             "We should never wrap a WorkerPrivate for a SharedWorker");
+
+  AssertIsOnParentThread();
+
+  // XXXkhuey this should not need to be rooted, the analysis is dumb.
+  // See bug 980181.
+  JS::Rooted<JSObject*> wrapper(aCx,
+    WorkerBinding::Wrap(aCx, ParentAsWorkerPrivate()));
+  if (wrapper) {
+    MOZ_ALWAYS_TRUE(TryPreserveWrapper(wrapper));
+  }
+
+  return wrapper;
+}
+
+template <class Derived>
+nsresult
+WorkerPrivateParent<Derived>::DispatchPrivate(WorkerRunnable* aRunnable,
+                                              nsIEventTarget* aSyncLoopTarget)
+{
+  // May be called on any thread!
+
+  WorkerPrivate* self = ParentAsWorkerPrivate();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    MOZ_ASSERT_IF(aSyncLoopTarget, self->mThread);
+
+    if (!self->mThread) {
+      if (ParentStatus() == Pending || self->mStatus == Pending) {
+        mPreStartRunnables.AppendElement(aRunnable);
+        return NS_OK;
+      }
+
+      NS_WARNING("Using a worker event target after the thread has already"
+                 "been released!");
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    if (self->mStatus == Dead ||
+        (!aSyncLoopTarget && ParentStatus() > Running)) {
+      NS_WARNING("A runnable was posted to a worker that is already shutting "
+                 "down!");
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    nsCOMPtr<nsIEventTarget> target;
+    if (aSyncLoopTarget) {
+      target = aSyncLoopTarget;
+    }
+    else {
+      target = self->mThread;
+    }
+
+    nsresult rv = target->Dispatch(aRunnable, NS_DISPATCH_NORMAL);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    mCondVar.Notify();
+  }
+
+  return NS_OK;
+}
+
+template <class Derived>
+nsresult
+WorkerPrivateParent<Derived>::DispatchControlRunnable(
+                                  WorkerControlRunnable* aWorkerControlRunnable)
+{
+  // May be called on any thread!
+
+  MOZ_ASSERT(aWorkerControlRunnable);
+
+  nsRefPtr<WorkerControlRunnable> runnable = aWorkerControlRunnable;
+
+  WorkerPrivate* self = ParentAsWorkerPrivate();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (self->mStatus == Dead) {
+      NS_WARNING("A control runnable was posted to a worker that is already "
+                 "shutting down!");
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    // Transfer ownership to the control queue.
+    self->mControlQueue.Push(runnable.forget().take());
+
+    if (JSContext* cx = self->mJSContext) {
+      MOZ_ASSERT(self->mThread);
+
+      JSRuntime* rt = JS_GetRuntime(cx);
+      MOZ_ASSERT(rt);
+
+      JS_RequestInterruptCallback(rt);
+    }
+
+    mCondVar.Notify();
+  }
+
+  return NS_OK;
+}
+
+template <class Derived>
+already_AddRefed<WorkerRunnable>
+WorkerPrivateParent<Derived>::MaybeWrapAsWorkerRunnable(nsIRunnable* aRunnable)
+{
+  // May be called on any thread!
+
+  MOZ_ASSERT(aRunnable);
+
+  nsRefPtr<WorkerRunnable> workerRunnable =
+    WorkerRunnable::FromRunnable(aRunnable);
+  if (workerRunnable) {
+    return workerRunnable.forget();
+  }
+
+  nsCOMPtr<nsICancelableRunnable> cancelable = do_QueryInterface(aRunnable);
+  if (!cancelable) {
+    MOZ_CRASH("All runnables destined for a worker thread must be cancelable!");
+  }
+
+  workerRunnable =
+    new ExternalRunnableWrapper(ParentAsWorkerPrivate(), cancelable);
+  return workerRunnable.forget();
+}
+
+template <class Derived>
+already_AddRefed<nsIEventTarget>
+WorkerPrivateParent<Derived>::GetEventTarget()
+{
+  WorkerPrivate* self = ParentAsWorkerPrivate();
+
+  nsCOMPtr<nsIEventTarget> target;
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (!mEventTarget &&
+        ParentStatus() <= Running &&
+        self->mStatus <= Running) {
+      mEventTarget = new EventTarget(self);
+    }
+
+    target = mEventTarget;
+  }
+
+  NS_WARN_IF_FALSE(target,
+                   "Requested event target for a worker that is already "
+                   "shutting down!");
+
+  return target.forget();
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::Start()
+{
+  // May be called on any thread!
+  {
+    MutexAutoLock lock(mMutex);
+
+    NS_ASSERTION(mParentStatus != Running, "How can this be?!");
+
+    if (mParentStatus == Pending) {
+      mParentStatus = Running;
+      return true;
+    }
+  }
+
+  return false;
+}
+
+// aCx is null when called from the finalizer
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::NotifyPrivate(JSContext* aCx, Status aStatus)
+{
+  AssertIsOnParentThread();
+
+  bool pending;
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mParentStatus >= aStatus) {
+      return true;
+    }
+
+    pending = mParentStatus == Pending;
+    mParentStatus = aStatus;
+  }
+
+  if (IsSharedWorker()) {
+    RuntimeService* runtime = RuntimeService::GetService();
+    MOZ_ASSERT(runtime);
+
+    runtime->ForgetSharedWorker(ParentAsWorkerPrivate());
+  }
+
+  if (pending) {
+    WorkerPrivate* self = ParentAsWorkerPrivate();
+
+#ifdef DEBUG
+    {
+      // Fake a thread here just so that our assertions don't go off for no
+      // reason.
+      nsIThread* currentThread = NS_GetCurrentThread();
+      MOZ_ASSERT(currentThread);
+
+      MOZ_ASSERT(!self->mPRThread);
+      self->mPRThread = PRThreadFromThread(currentThread);
+      MOZ_ASSERT(self->mPRThread);
+    }
+#endif
+
+    // Worker never got a chance to run, go ahead and delete it.
+    self->ScheduleDeletion(WorkerPrivate::WorkerNeverRan);
+    return true;
+  }
+
+  // Only top-level workers should have a synchronize runnable.
+  MOZ_ASSERT_IF(mSynchronizeRunnable.get(), !GetParent());
+  mSynchronizeRunnable.Revoke();
+
+  NS_ASSERTION(aStatus != Terminating || mQueuedRunnables.IsEmpty(),
+               "Shouldn't have anything queued!");
+
+  // Anything queued will be discarded.
+  mQueuedRunnables.Clear();
+
+  nsRefPtr<NotifyRunnable> runnable =
+    new NotifyRunnable(ParentAsWorkerPrivate(), aStatus);
+  return runnable->Dispatch(aCx);
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::Suspend(JSContext* aCx, nsPIDOMWindow* aWindow)
+{
+  AssertIsOnParentThread();
+  MOZ_ASSERT(aCx);
+
+  // Shared workers are only suspended if all of their owning documents are
+  // suspended.
+  if (IsSharedWorker()) {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(mSharedWorkers.Count());
+
+    struct Closure
+    {
+      nsPIDOMWindow* mWindow;
+      bool mAllSuspended;
+
+      Closure(nsPIDOMWindow* aWindow)
+      : mWindow(aWindow), mAllSuspended(true)
+      {
+        AssertIsOnMainThread();
+        // aWindow may be null here.
+      }
+
+      static PLDHashOperator
+      Suspend(const uint64_t& aKey,
+              SharedWorker* aSharedWorker,
+              void* aClosure)
+      {
+        AssertIsOnMainThread();
+        MOZ_ASSERT(aSharedWorker);
+        MOZ_ASSERT(aClosure);
+
+        auto closure = static_cast<Closure*>(aClosure);
+
+        if (closure->mWindow && aSharedWorker->GetOwner() == closure->mWindow) {
+          // Calling Suspend() may change the refcount, ensure that the worker
+          // outlives this call.
+          nsRefPtr<SharedWorker> kungFuDeathGrip = aSharedWorker;
+
+          aSharedWorker->Suspend();
+        } else {
+          MOZ_ASSERT_IF(aSharedWorker->GetOwner() && closure->mWindow,
+                        !SameCOMIdentity(aSharedWorker->GetOwner(),
+                                         closure->mWindow));
+          if (!aSharedWorker->IsSuspended()) {
+            closure->mAllSuspended = false;
+          }
+        }
+        return PL_DHASH_NEXT;
+      }
+    };
+
+    Closure closure(aWindow);
+
+    mSharedWorkers.EnumerateRead(Closure::Suspend, &closure);
+
+    if (!closure.mAllSuspended || mParentSuspended) {
+      return true;
+    }
+  }
+
+//  MOZ_ASSERT(!mParentSuspended, "Suspended more than once!");
+
+  mParentSuspended = true;
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mParentStatus >= Terminating) {
+      return true;
+    }
+  }
+
+  nsRefPtr<SuspendRunnable> runnable =
+    new SuspendRunnable(ParentAsWorkerPrivate());
+  if (!runnable->Dispatch(aCx)) {
+    return false;
+  }
+
+  return true;
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::Resume(JSContext* aCx, nsPIDOMWindow* aWindow)
+{
+  AssertIsOnParentThread();
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT_IF(!IsSharedWorker(), mParentSuspended);
+
+  // Shared workers are resumed if any of their owning documents are resumed.
+  if (IsSharedWorker()) {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(mSharedWorkers.Count());
+
+    struct Closure
+    {
+      nsPIDOMWindow* mWindow;
+      bool mAnyRunning;
+
+      Closure(nsPIDOMWindow* aWindow)
+      : mWindow(aWindow), mAnyRunning(false)
+      {
+        AssertIsOnMainThread();
+        // aWindow may be null here.
+      }
+
+      static PLDHashOperator
+      Resume(const uint64_t& aKey,
+              SharedWorker* aSharedWorker,
+              void* aClosure)
+      {
+        AssertIsOnMainThread();
+        MOZ_ASSERT(aSharedWorker);
+        MOZ_ASSERT(aClosure);
+
+        auto closure = static_cast<Closure*>(aClosure);
+
+        if (closure->mWindow && aSharedWorker->GetOwner() == closure->mWindow) {
+          // Calling Resume() may change the refcount, ensure that the worker
+          // outlives this call.
+          nsRefPtr<SharedWorker> kungFuDeathGrip = aSharedWorker;
+
+          aSharedWorker->Resume();
+          closure->mAnyRunning = true;
+        } else {
+          MOZ_ASSERT_IF(aSharedWorker->GetOwner() && closure->mWindow,
+                        !SameCOMIdentity(aSharedWorker->GetOwner(),
+                                         closure->mWindow));
+          if (!aSharedWorker->IsSuspended()) {
+            closure->mAnyRunning = true;
+          }
+        }
+        return PL_DHASH_NEXT;
+      }
+    };
+
+    Closure closure(aWindow);
+
+    mSharedWorkers.EnumerateRead(Closure::Resume, &closure);
+
+    if (!closure.mAnyRunning || !mParentSuspended) {
+      return true;
+    }
+  }
+
+  MOZ_ASSERT(mParentSuspended);
+
+  mParentSuspended = false;
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mParentStatus >= Terminating) {
+      return true;
+    }
+  }
+
+  // Only top-level workers should have a synchronize runnable.
+  MOZ_ASSERT_IF(mSynchronizeRunnable.get(), !GetParent());
+  mSynchronizeRunnable.Revoke();
+
+  // Execute queued runnables before waking up the worker, otherwise the worker
+  // could post new messages before we run those that have been queued.
+  if (!mQueuedRunnables.IsEmpty()) {
+    AssertIsOnMainThread();
+    MOZ_ASSERT(IsDedicatedWorker());
+
+    nsTArray<nsCOMPtr<nsIRunnable>> runnables;
+    mQueuedRunnables.SwapElements(runnables);
+
+    for (uint32_t index = 0; index < runnables.Length(); index++) {
+      runnables[index]->Run();
+    }
+  }
+
+  nsRefPtr<ResumeRunnable> runnable =
+    new ResumeRunnable(ParentAsWorkerPrivate());
+  if (!runnable->Dispatch(aCx)) {
+    return false;
+  }
+
+  return true;
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::SynchronizeAndResume(
+                                               JSContext* aCx,
+                                               nsPIDOMWindow* aWindow,
+                                               nsIScriptContext* aScriptContext)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(!GetParent());
+  MOZ_ASSERT_IF(IsDedicatedWorker(), mParentSuspended);
+
+  // NB: There may be pending unqueued messages.  If we resume here we will
+  // execute those messages out of order.  Instead we post an event to the
+  // end of the event queue, allowing all of the outstanding messages to be
+  // queued up in order on the worker.  Then and only then we execute all of
+  // the messages.
+
+  nsRefPtr<SynchronizeAndResumeRunnable> runnable =
+    new SynchronizeAndResumeRunnable(ParentAsWorkerPrivate(), aWindow,
+                                     aScriptContext);
+  if (NS_FAILED(NS_DispatchToCurrentThread(runnable))) {
+    JS_ReportError(aCx, "Failed to dispatch to current thread!");
+    return false;
+  }
+
+  mSynchronizeRunnable = runnable;
+  return true;
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::Close(JSContext* aCx)
+{
+  AssertIsOnParentThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mParentStatus < Closing) {
+      mParentStatus = Closing;
+    }
+  }
+
+  return true;
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::ModifyBusyCount(JSContext* aCx, bool aIncrease)
+{
+  AssertIsOnParentThread();
+
+  NS_ASSERTION(aIncrease || mBusyCount, "Mismatched busy count mods!");
+
+  if (aIncrease) {
+    mBusyCount++;
+    return true;
+  }
+
+  if (--mBusyCount == 0) {
+
+    bool shouldCancel;
+    {
+      MutexAutoLock lock(mMutex);
+      shouldCancel = mParentStatus == Terminating;
+    }
+
+    if (shouldCancel && !Cancel(aCx)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::ForgetMainThreadObjects(
+                                      nsTArray<nsCOMPtr<nsISupports> >& aDoomed)
+{
+  AssertIsOnParentThread();
+  MOZ_ASSERT(!mMainThreadObjectsForgotten);
+
+  static const uint32_t kDoomedCount = 7;
+
+  aDoomed.SetCapacity(kDoomedCount);
+
+  SwapToISupportsArray(mLoadInfo.mWindow, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mScriptContext, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mBaseURI, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mResolvedScriptURI, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mPrincipal, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mChannel, aDoomed);
+  SwapToISupportsArray(mLoadInfo.mCSP, aDoomed);
+  // Before adding anything here update kDoomedCount above!
+
+  MOZ_ASSERT(aDoomed.Length() == kDoomedCount);
+
+  mMainThreadObjectsForgotten = true;
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::PostMessageInternal(
+                                            JSContext* aCx,
+                                            JS::Handle<JS::Value> aMessage,
+                                            const Optional<Sequence<JS::Value> >& aTransferable,
+                                            bool aToMessagePort,
+                                            uint64_t aMessagePortSerial,
+                                            ErrorResult& aRv)
+{
+  AssertIsOnParentThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+    if (mParentStatus > Running) {
+      return;
+    }
+  }
+
+  JSStructuredCloneCallbacks* callbacks;
+  if (GetParent()) {
+    if (IsChromeWorker()) {
+      callbacks = &gChromeWorkerStructuredCloneCallbacks;
+    }
+    else {
+      callbacks = &gWorkerStructuredCloneCallbacks;
+    }
+  }
+  else {
+    AssertIsOnMainThread();
+
+    if (IsChromeWorker()) {
+      callbacks = &gMainThreadChromeWorkerStructuredCloneCallbacks;
+    }
+    else {
+      callbacks = &gMainThreadWorkerStructuredCloneCallbacks;
+    }
+  }
+
+  JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
+  if (aTransferable.WasPassed()) {
+    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
+
+    // The input sequence only comes from the generated bindings code, which
+    // ensures it is rooted.
+    JS::HandleValueArray elements =
+      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
+                                               realTransferable.Elements());
+
+    JSObject* array =
+      JS_NewArrayObject(aCx, elements);
+    if (!array) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+    transferable.setObject(*array);
+  }
+
+  nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+
+  JSAutoStructuredCloneBuffer buffer;
+  if (!buffer.write(aCx, aMessage, transferable, callbacks, &clonedObjects)) {
+    aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
+    return;
+  }
+
+  nsRefPtr<MessageEventRunnable> runnable =
+    new MessageEventRunnable(ParentAsWorkerPrivate(),
+                             WorkerRunnable::WorkerThreadModifyBusyCount,
+                             Move(buffer), clonedObjects, aToMessagePort,
+                             aMessagePortSerial);
+  if (!runnable->Dispatch(aCx)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::PostMessageToMessagePort(
+                             JSContext* aCx,
+                             uint64_t aMessagePortSerial,
+                             JS::Handle<JS::Value> aMessage,
+                             const Optional<Sequence<JS::Value>>& aTransferable,
+                             ErrorResult& aRv)
+{
+  AssertIsOnMainThread();
+
+  PostMessageInternal(aCx, aMessage, aTransferable, true, aMessagePortSerial,
+                      aRv);
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::DispatchMessageEventToMessagePort(
+                                JSContext* aCx, uint64_t aMessagePortSerial,
+                                JSAutoStructuredCloneBuffer&& aBuffer,
+                                nsTArray<nsCOMPtr<nsISupports>>& aClonedObjects)
+{
+  AssertIsOnMainThread();
+
+  JSAutoStructuredCloneBuffer buffer(Move(aBuffer));
+
+  nsTArray<nsCOMPtr<nsISupports>> clonedObjects;
+  clonedObjects.SwapElements(aClonedObjects);
+
+  SharedWorker* sharedWorker;
+  if (!mSharedWorkers.Get(aMessagePortSerial, &sharedWorker)) {
+    // SharedWorker has already been unregistered?
+    return true;
+  }
+
+  nsRefPtr<MessagePort> port = sharedWorker->Port();
+  NS_ASSERTION(port, "SharedWorkers always have a port!");
+
+  if (port->IsClosed()) {
+    return true;
+  }
+
+  nsCOMPtr<nsIScriptGlobalObject> sgo;
+  port->GetParentObject(getter_AddRefs(sgo));
+  MOZ_ASSERT(sgo, "Should never happen if IsClosed() returned false!");
+  MOZ_ASSERT(sgo->GetGlobalJSObject());
+
+  nsCOMPtr<nsIScriptContext> scx = sgo->GetContext();
+  MOZ_ASSERT_IF(scx, scx->GetNativeContext());
+
+  AutoPushJSContext cx(scx ? scx->GetNativeContext() : aCx);
+  JSAutoCompartment(cx, sgo->GetGlobalJSObject());
+
+  JS::Rooted<JS::Value> data(cx);
+  if (!buffer.read(cx, &data, WorkerStructuredCloneCallbacks(true))) {
+    return false;
+  }
+
+  buffer.clear();
+
+  nsRefPtr<MessageEvent> event = new MessageEvent(port, nullptr, nullptr);
+  nsresult rv =
+    event->InitMessageEvent(NS_LITERAL_STRING("message"), false, false, data,
+                            EmptyString(), EmptyString(), nullptr);
+  if (NS_FAILED(rv)) {
+    xpc::Throw(cx, rv);
+    return false;
+  }
+
+  event->SetTrusted(true);
+
+  nsTArray<nsRefPtr<MessagePortBase>> ports;
+  ports.AppendElement(port);
+
+  nsRefPtr<MessagePortList> portList = new MessagePortList(port, ports);
+  event->SetPorts(portList);
+
+  nsCOMPtr<nsIDOMEvent> domEvent;
+  CallQueryInterface(event.get(), getter_AddRefs(domEvent));
+  NS_ASSERTION(domEvent, "This should never fail!");
+
+  bool ignored;
+  rv = port->DispatchEvent(domEvent, &ignored);
+  if (NS_FAILED(rv)) {
+    xpc::Throw(cx, rv);
+    return false;
+  }
+
+  return true;
+}
+
+template <class Derived>
+uint64_t
+WorkerPrivateParent<Derived>::GetInnerWindowId()
+{
+  AssertIsOnMainThread();
+  NS_ASSERTION(!mLoadInfo.mWindow || mLoadInfo.mWindow->IsInnerWindow(),
+               "Outer window?");
+  return mLoadInfo.mWindow ? mLoadInfo.mWindow->WindowID() : 0;
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UpdateRuntimeAndContextOptions(
+                                    JSContext* aCx,
+                                    const JS::RuntimeOptions& aRuntimeOptions,
+                                    const JS::ContextOptions& aContentCxOptions,
+                                    const JS::ContextOptions& aChromeCxOptions)
+{
+  AssertIsOnParentThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+    mJSSettings.runtimeOptions = aRuntimeOptions;
+    mJSSettings.content.contextOptions = aContentCxOptions;
+    mJSSettings.chrome.contextOptions = aChromeCxOptions;
+  }
+
+  nsRefPtr<UpdateRuntimeAndContextOptionsRunnable> runnable =
+    new UpdateRuntimeAndContextOptionsRunnable(ParentAsWorkerPrivate(),
+                                               aRuntimeOptions,
+                                               aContentCxOptions,
+                                               aChromeCxOptions);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to update worker context options!");
+    JS_ClearPendingException(aCx);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UpdatePreference(JSContext* aCx, WorkerPreference aPref, bool aValue)
+{
+  AssertIsOnParentThread();
+  MOZ_ASSERT(aPref >= 0 && aPref < WORKERPREF_COUNT);
+
+  nsRefPtr<UpdatePreferenceRunnable> runnable =
+    new UpdatePreferenceRunnable(ParentAsWorkerPrivate(), aPref, aValue);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to update worker preferences!");
+    JS_ClearPendingException(aCx);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UpdateJSWorkerMemoryParameter(JSContext* aCx,
+                                                            JSGCParamKey aKey,
+                                                            uint32_t aValue)
+{
+  AssertIsOnParentThread();
+
+  bool found = false;
+
+  {
+    MutexAutoLock lock(mMutex);
+    found = mJSSettings.ApplyGCSetting(aKey, aValue);
+  }
+
+  if (found) {
+    nsRefPtr<UpdateJSWorkerMemoryParameterRunnable> runnable =
+      new UpdateJSWorkerMemoryParameterRunnable(ParentAsWorkerPrivate(), aKey,
+                                                aValue);
+    if (!runnable->Dispatch(aCx)) {
+      NS_WARNING("Failed to update memory parameter!");
+      JS_ClearPendingException(aCx);
+    }
+  }
+}
+
+#ifdef JS_GC_ZEAL
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UpdateGCZeal(JSContext* aCx, uint8_t aGCZeal,
+                                           uint32_t aFrequency)
+{
+  AssertIsOnParentThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+    mJSSettings.gcZeal = aGCZeal;
+    mJSSettings.gcZealFrequency = aFrequency;
+  }
+
+  nsRefPtr<UpdateGCZealRunnable> runnable =
+    new UpdateGCZealRunnable(ParentAsWorkerPrivate(), aGCZeal, aFrequency);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to update worker gczeal!");
+    JS_ClearPendingException(aCx);
+  }
+}
+#endif
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::GarbageCollect(JSContext* aCx, bool aShrinking)
+{
+  AssertIsOnParentThread();
+
+  nsRefPtr<GarbageCollectRunnable> runnable =
+    new GarbageCollectRunnable(ParentAsWorkerPrivate(), aShrinking,
+                               /* collectChildren = */ true);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to GC worker!");
+    JS_ClearPendingException(aCx);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::CycleCollect(JSContext* aCx, bool aDummy)
+{
+  AssertIsOnParentThread();
+
+  nsRefPtr<CycleCollectRunnable> runnable =
+    new CycleCollectRunnable(ParentAsWorkerPrivate(),
+                             /* collectChildren = */ true);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to CC worker!");
+    JS_ClearPendingException(aCx);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::OfflineStatusChangeEvent(JSContext* aCx, bool aIsOffline)
+{
+  AssertIsOnParentThread();
+
+  nsRefPtr<OfflineStatusChangeRunnable> runnable =
+    new OfflineStatusChangeRunnable(ParentAsWorkerPrivate(), aIsOffline);
+  if (!runnable->Dispatch(aCx)) {
+    NS_WARNING("Failed to dispatch offline status change event!");
+    JS_ClearPendingException(aCx);
+  }
+}
+
+void
+WorkerPrivate::OfflineStatusChangeEventInternal(JSContext* aCx, bool aIsOffline)
+{
+  AssertIsOnWorkerThread();
+
+  for (uint32_t index = 0; index < mChildWorkers.Length(); ++index) {
+    mChildWorkers[index]->OfflineStatusChangeEvent(aCx, aIsOffline);
+  }
+
+  mOnLine = !aIsOffline;
+  WorkerGlobalScope* globalScope = GlobalScope();
+  nsRefPtr<WorkerNavigator> nav = globalScope->GetExistingNavigator();
+  if (nav) {
+    nav->SetOnLine(mOnLine);
+  }
+
+  nsString eventType;
+  if (aIsOffline) {
+    eventType.AssignLiteral("offline");
+  } else {
+    eventType.AssignLiteral("online");
+  }
+
+  nsCOMPtr<nsIDOMEvent> event;
+  nsresult rv =
+    NS_NewDOMEvent(getter_AddRefs(event), globalScope, nullptr, nullptr);
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  rv = event->InitEvent(eventType, false, false);
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  event->SetTrusted(true);
+
+  globalScope->DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+}
+
+template <class Derived>
+bool
+WorkerPrivateParent<Derived>::RegisterSharedWorker(JSContext* aCx,
+                                                   SharedWorker* aSharedWorker)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(aSharedWorker);
+  MOZ_ASSERT(IsSharedWorker());
+  MOZ_ASSERT(!mSharedWorkers.Get(aSharedWorker->Serial()));
+
+  nsRefPtr<MessagePortRunnable> runnable =
+    new MessagePortRunnable(ParentAsWorkerPrivate(), aSharedWorker->Serial(),
+                            true);
+  if (!runnable->Dispatch(aCx)) {
+    return false;
+  }
+
+  mSharedWorkers.Put(aSharedWorker->Serial(), aSharedWorker);
+
+  // If there were other SharedWorker objects attached to this worker then they
+  // may all have been suspended and this worker would need to be resumed.
+  if (mSharedWorkers.Count() > 1 && !Resume(aCx, nullptr)) {
+    return false;
+  }
+
+  return true;
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UnregisterSharedWorker(
+                                                    JSContext* aCx,
+                                                    SharedWorker* aSharedWorker)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(aSharedWorker);
+  MOZ_ASSERT(IsSharedWorker());
+  MOZ_ASSERT(mSharedWorkers.Get(aSharedWorker->Serial()));
+
+  nsRefPtr<MessagePortRunnable> runnable =
+    new MessagePortRunnable(ParentAsWorkerPrivate(), aSharedWorker->Serial(),
+                            false);
+  if (!runnable->Dispatch(aCx)) {
+    JS_ReportPendingException(aCx);
+  }
+
+  mSharedWorkers.Remove(aSharedWorker->Serial());
+
+  // If there are still SharedWorker objects attached to this worker then they
+  // may all be suspended and this worker would need to be suspended. Otherwise,
+  // if that was the last SharedWorker then it's time to cancel this worker.
+  if (mSharedWorkers.Count()) {
+    if (!Suspend(aCx, nullptr)) {
+      JS_ReportPendingException(aCx);
+    }
+  } else if (!Cancel(aCx)) {
+    JS_ReportPendingException(aCx);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::BroadcastErrorToSharedWorkers(
+                                                    JSContext* aCx,
+                                                    const nsAString& aMessage,
+                                                    const nsAString& aFilename,
+                                                    const nsAString& aLine,
+                                                    uint32_t aLineNumber,
+                                                    uint32_t aColumnNumber,
+                                                    uint32_t aFlags)
+{
+  AssertIsOnMainThread();
+
+  nsAutoTArray<nsRefPtr<SharedWorker>, 10> sharedWorkers;
+  GetAllSharedWorkers(sharedWorkers);
+
+  if (sharedWorkers.IsEmpty()) {
+    return;
+  }
+
+  nsAutoTArray<WindowAction, 10> windowActions;
+  nsresult rv;
+
+  // First fire the error event at all SharedWorker objects. This may include
+  // multiple objects in a single window as well as objects in different
+  // windows.
+  for (uint32_t index = 0; index < sharedWorkers.Length(); index++) {
+    nsRefPtr<SharedWorker>& sharedWorker = sharedWorkers[index];
+
+    // May be null.
+    nsPIDOMWindow* window = sharedWorker->GetOwner();
+
+    uint32_t actionsIndex = windowActions.LastIndexOf(WindowAction(window));
+
+    nsIGlobalObject* global = sharedWorker->GetParentObject();
+    AutoJSAPIWithErrorsReportedToWindow jsapi(global);
+    JSContext* cx = jsapi.cx();
+    JSAutoCompartment ac(cx, global->GetGlobalJSObject());
+
+    RootedDictionary<ErrorEventInit> errorInit(aCx);
+    errorInit.mBubbles = false;
+    errorInit.mCancelable = true;
+    errorInit.mMessage = aMessage;
+    errorInit.mFilename = aFilename;
+    errorInit.mLineno = aLineNumber;
+    errorInit.mColno = aColumnNumber;
+
+    nsRefPtr<ErrorEvent> errorEvent =
+      ErrorEvent::Constructor(sharedWorker, NS_LITERAL_STRING("error"),
+                              errorInit);
+    if (!errorEvent) {
+      Throw(cx, NS_ERROR_UNEXPECTED);
+      JS_ReportPendingException(cx);
+      continue;
+    }
+
+    errorEvent->SetTrusted(true);
+
+    bool defaultActionEnabled;
+    nsresult rv = sharedWorker->DispatchEvent(errorEvent, &defaultActionEnabled);
+    if (NS_FAILED(rv)) {
+      Throw(cx, rv);
+      JS_ReportPendingException(cx);
+      continue;
+    }
+
+    if (defaultActionEnabled) {
+      // Add the owning window to our list so that we will fire an error event
+      // at it later.
+      if (!windowActions.Contains(window)) {
+        windowActions.AppendElement(WindowAction(window, cx));
+      }
+    } else if (actionsIndex != windowActions.NoIndex) {
+      // Any listener that calls preventDefault() will prevent the window from
+      // receiving the error event.
+      windowActions[actionsIndex].mDefaultAction = false;
+    }
+  }
+
+  // If there are no windows to consider further then we're done.
+  if (windowActions.IsEmpty()) {
+    return;
+  }
+
+  bool shouldLogErrorToConsole = true;
+
+  // Now fire error events at all the windows remaining.
+  for (uint32_t index = 0; index < windowActions.Length(); index++) {
+    WindowAction& windowAction = windowActions[index];
+
+    // If there is no window or the script already called preventDefault then
+    // skip this window.
+    if (!windowAction.mWindow || !windowAction.mDefaultAction) {
+      continue;
+    }
+
+    JSContext* cx = windowAction.mJSContext;
+
+    AutoCxPusher autoPush(cx);
+
+    nsCOMPtr<nsIScriptGlobalObject> sgo =
+      do_QueryInterface(windowAction.mWindow);
+    MOZ_ASSERT(sgo);
+
+    MOZ_ASSERT(NS_IsMainThread());
+    RootedDictionary<ErrorEventInit> init(aCx);
+    init.mLineno = aLineNumber;
+    init.mFilename = aFilename;
+    init.mMessage = aMessage;
+    init.mCancelable = true;
+    init.mBubbles = true;
+
+    nsEventStatus status = nsEventStatus_eIgnore;
+    rv = sgo->HandleScriptError(init, &status);
+    if (NS_FAILED(rv)) {
+      Throw(cx, rv);
+      JS_ReportPendingException(cx);
+      continue;
+    }
+
+    if (status == nsEventStatus_eConsumeNoDefault) {
+      shouldLogErrorToConsole = false;
+    }
+  }
+
+  // Finally log a warning in the console if no window tried to prevent it.
+  if (shouldLogErrorToConsole) {
+    LogErrorToConsole(aMessage, aFilename, aLine, aLineNumber, aColumnNumber,
+                      aFlags, 0);
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::GetAllSharedWorkers(
+                               nsTArray<nsRefPtr<SharedWorker>>& aSharedWorkers)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(IsSharedWorker());
+
+  struct Helper
+  {
+    static PLDHashOperator
+    Collect(const uint64_t& aKey,
+            SharedWorker* aSharedWorker,
+            void* aClosure)
+    {
+      AssertIsOnMainThread();
+      MOZ_ASSERT(aSharedWorker);
+      MOZ_ASSERT(aClosure);
+
+      auto array = static_cast<nsTArray<nsRefPtr<SharedWorker>>*>(aClosure);
+      array->AppendElement(aSharedWorker);
+
+      return PL_DHASH_NEXT;
+    }
+  };
+
+  if (!aSharedWorkers.IsEmpty()) {
+    aSharedWorkers.Clear();
+  }
+
+  mSharedWorkers.EnumerateRead(Helper::Collect, &aSharedWorkers);
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::CloseSharedWorkersForWindow(
+                                                         nsPIDOMWindow* aWindow)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(IsSharedWorker());
+  MOZ_ASSERT(aWindow);
+
+  struct Closure
+  {
+    nsPIDOMWindow* mWindow;
+    nsAutoTArray<nsRefPtr<SharedWorker>, 10> mSharedWorkers;
+
+    Closure(nsPIDOMWindow* aWindow)
+    : mWindow(aWindow)
+    {
+      AssertIsOnMainThread();
+      MOZ_ASSERT(aWindow);
+    }
+
+    static PLDHashOperator
+    Collect(const uint64_t& aKey,
+            SharedWorker* aSharedWorker,
+            void* aClosure)
+    {
+      AssertIsOnMainThread();
+      MOZ_ASSERT(aSharedWorker);
+      MOZ_ASSERT(aClosure);
+
+      auto closure = static_cast<Closure*>(aClosure);
+      MOZ_ASSERT(closure->mWindow);
+
+      if (aSharedWorker->GetOwner() == closure->mWindow) {
+        closure->mSharedWorkers.AppendElement(aSharedWorker);
+      } else {
+        MOZ_ASSERT(!SameCOMIdentity(aSharedWorker->GetOwner(),
+                                    closure->mWindow));
+      }
+
+      return PL_DHASH_NEXT;
+    }
+  };
+
+  Closure closure(aWindow);
+
+  mSharedWorkers.EnumerateRead(Closure::Collect, &closure);
+
+  for (uint32_t index = 0; index < closure.mSharedWorkers.Length(); index++) {
+    closure.mSharedWorkers[index]->Close();
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::WorkerScriptLoaded()
+{
+  AssertIsOnMainThread();
+
+  if (IsSharedWorker()) {
+    // No longer need to hold references to the window or document we came from.
+    mLoadInfo.mWindow = nullptr;
+    mLoadInfo.mScriptContext = nullptr;
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::SetBaseURI(nsIURI* aBaseURI)
+{
+  AssertIsOnMainThread();
+
+  if (!mLoadInfo.mBaseURI) {
+    NS_ASSERTION(GetParent(), "Shouldn't happen without a parent!");
+    mLoadInfo.mResolvedScriptURI = aBaseURI;
+  }
+
+  mLoadInfo.mBaseURI = aBaseURI;
+
+  if (NS_FAILED(aBaseURI->GetSpec(mLocationInfo.mHref))) {
+    mLocationInfo.mHref.Truncate();
+  }
+
+  if (NS_FAILED(aBaseURI->GetHost(mLocationInfo.mHostname))) {
+    mLocationInfo.mHostname.Truncate();
+  }
+
+  if (NS_FAILED(aBaseURI->GetPath(mLocationInfo.mPathname))) {
+    mLocationInfo.mPathname.Truncate();
+  }
+
+  nsCString temp;
+
+  nsCOMPtr<nsIURL> url(do_QueryInterface(aBaseURI));
+  if (url && NS_SUCCEEDED(url->GetQuery(temp)) && !temp.IsEmpty()) {
+    mLocationInfo.mSearch.AssignLiteral("?");
+    mLocationInfo.mSearch.Append(temp);
+  }
+
+  if (NS_SUCCEEDED(aBaseURI->GetRef(temp)) && !temp.IsEmpty()) {
+    nsCOMPtr<nsITextToSubURI> converter =
+      do_GetService(NS_ITEXTTOSUBURI_CONTRACTID);
+    if (converter) {
+      nsCString charset;
+      nsAutoString unicodeRef;
+      if (NS_SUCCEEDED(aBaseURI->GetOriginCharset(charset)) &&
+          NS_SUCCEEDED(converter->UnEscapeURIForUI(charset, temp,
+                                                   unicodeRef))) {
+        mLocationInfo.mHash.AssignLiteral("#");
+        mLocationInfo.mHash.Append(NS_ConvertUTF16toUTF8(unicodeRef));
+      }
+    }
+
+    if (mLocationInfo.mHash.IsEmpty()) {
+      mLocationInfo.mHash.AssignLiteral("#");
+      mLocationInfo.mHash.Append(temp);
+    }
+  }
+
+  if (NS_SUCCEEDED(aBaseURI->GetScheme(mLocationInfo.mProtocol))) {
+    mLocationInfo.mProtocol.AppendLiteral(":");
+  }
+  else {
+    mLocationInfo.mProtocol.Truncate();
+  }
+
+  int32_t port;
+  if (NS_SUCCEEDED(aBaseURI->GetPort(&port)) && port != -1) {
+    mLocationInfo.mPort.AppendInt(port);
+
+    nsAutoCString host(mLocationInfo.mHostname);
+    host.AppendLiteral(":");
+    host.Append(mLocationInfo.mPort);
+
+    mLocationInfo.mHost.Assign(host);
+  }
+  else {
+    mLocationInfo.mHost.Assign(mLocationInfo.mHostname);
+  }
+
+  nsContentUtils::GetUTFNonNullOrigin(aBaseURI, mLocationInfo.mOrigin);
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::SetPrincipal(nsIPrincipal* aPrincipal)
+{
+  AssertIsOnMainThread();
+
+  mLoadInfo.mPrincipal = aPrincipal;
+  mLoadInfo.mPrincipalIsSystem = nsContentUtils::IsSystemPrincipal(aPrincipal);
+  uint16_t appStatus = aPrincipal->GetAppStatus();
+  mLoadInfo.mIsInPrivilegedApp =
+    (appStatus == nsIPrincipal::APP_STATUS_CERTIFIED ||
+     appStatus == nsIPrincipal::APP_STATUS_PRIVILEGED);
+  mLoadInfo.mIsInCertifiedApp = (appStatus == nsIPrincipal::APP_STATUS_CERTIFIED);
+}
+
+template <class Derived>
+JSContext*
+WorkerPrivateParent<Derived>::ParentJSContext() const
+{
+  AssertIsOnParentThread();
+
+  if (mParent) {
+    return mParent->GetJSContext();
+  }
+
+  AssertIsOnMainThread();
+
+  return mLoadInfo.mScriptContext ?
+         mLoadInfo.mScriptContext->GetNativeContext() :
+         nsContentUtils::GetSafeJSContext();
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::RegisterHostObjectURI(const nsACString& aURI)
+{
+  AssertIsOnMainThread();
+  mHostObjectURIs.AppendElement(aURI);
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::UnregisterHostObjectURI(const nsACString& aURI)
+{
+  AssertIsOnMainThread();
+  mHostObjectURIs.RemoveElement(aURI);
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::StealHostObjectURIs(nsTArray<nsCString>& aArray)
+{
+  aArray.SwapElements(mHostObjectURIs);
+}
+
+template <class Derived>
+NS_IMPL_ADDREF_INHERITED(WorkerPrivateParent<Derived>, DOMEventTargetHelper)
+
+template <class Derived>
+NS_IMPL_RELEASE_INHERITED(WorkerPrivateParent<Derived>, DOMEventTargetHelper)
+
+template <class Derived>
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(WorkerPrivateParent<Derived>)
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+template <class Derived>
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(WorkerPrivateParent<Derived>,
+                                                  DOMEventTargetHelper)
+  tmp->AssertIsOnParentThread();
+
+  // The WorkerPrivate::mSelfRef has a reference to itself, which is really
+  // held by the worker thread.  We traverse this reference if and only if our
+  // busy count is zero and we have not released the main thread reference.
+  // We do not unlink it.  This allows the CC to break cycles involving the
+  // WorkerPrivate and begin shutting it down (which does happen in unlink) but
+  // ensures that the WorkerPrivate won't be deleted before we're done shutting
+  // down the thread.
+
+  if (!tmp->mBusyCount && !tmp->mMainThreadObjectsForgotten) {
+    NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSelfRef)
+  }
+
+  // The various strong references in LoadInfo are managed manually and cannot
+  // be cycle collected.
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+template <class Derived>
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(WorkerPrivateParent<Derived>,
+                                                DOMEventTargetHelper)
+  tmp->Terminate(nullptr);
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+template <class Derived>
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(WorkerPrivateParent<Derived>,
+                                               DOMEventTargetHelper)
+  tmp->AssertIsOnParentThread();
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+#ifdef DEBUG
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::AssertIsOnParentThread() const
+{
+  if (GetParent()) {
+    GetParent()->AssertIsOnWorkerThread();
+  }
+  else {
+    AssertIsOnMainThread();
+  }
+}
+
+template <class Derived>
+void
+WorkerPrivateParent<Derived>::AssertInnerWindowIsCorrect() const
+{
+  AssertIsOnParentThread();
+
+  // Only care about top level workers from windows.
+  if (mParent || !mLoadInfo.mWindow) {
+    return;
+  }
+
+  AssertIsOnMainThread();
+
+  nsPIDOMWindow* outer = mLoadInfo.mWindow->GetOuterWindow();
+  NS_ASSERTION(outer && outer->GetCurrentInnerWindow() == mLoadInfo.mWindow,
+               "Inner window no longer correct!");
+}
+
+#endif
+WorkerPrivate::WorkerPrivate(JSContext* aCx,
+                             WorkerPrivate* aParent,
+                             const nsAString& aScriptURL,
+                             bool aIsChromeWorker, WorkerType aWorkerType,
+                             const nsACString& aSharedWorkerName,
+                             LoadInfo& aLoadInfo)
+: WorkerPrivateParent<WorkerPrivate>(aCx, aParent, aScriptURL,
+                                     aIsChromeWorker, aWorkerType,
+                                     aSharedWorkerName, aLoadInfo),
+  mJSContext(nullptr), mErrorHandlerRecursionCount(0), mNextTimeoutId(1),
+  mStatus(Pending), mSuspended(false), mTimerRunning(false),
+  mRunningExpiredTimeouts(false), mCloseHandlerStarted(false),
+  mCloseHandlerFinished(false), mMemoryReporterRunning(false),
+  mBlockedForMemoryReporter(false), mCancelAllPendingRunnables(false),
+  mPeriodicGCTimerRunning(false), mIdleGCTimerRunning(false)
+#ifdef DEBUG
+  , mPRThread(nullptr)
+#endif
+{
+  MOZ_ASSERT_IF(IsSharedWorker(), !aSharedWorkerName.IsVoid());
+  MOZ_ASSERT_IF(!IsSharedWorker(), aSharedWorkerName.IsEmpty());
+
+  if (aParent) {
+    aParent->AssertIsOnWorkerThread();
+    aParent->GetAllPreferences(mPreferences);
+    mOnLine = aParent->OnLine();
+  }
+  else {
+    AssertIsOnMainThread();
+    RuntimeService::GetDefaultPreferences(mPreferences);
+    mOnLine = !NS_IsOffline();
+  }
+}
+
+WorkerPrivate::~WorkerPrivate()
+{
+}
+
+// static
+already_AddRefed<WorkerPrivate>
+WorkerPrivate::Constructor(const GlobalObject& aGlobal,
+                           const nsAString& aScriptURL,
+                           ErrorResult& aRv)
+{
+  return WorkerPrivate::Constructor(aGlobal, aScriptURL, false,
+                                    WorkerTypeDedicated, EmptyCString(),
+                                    nullptr, aRv);
+}
+
+// static
+bool
+WorkerPrivate::WorkerAvailable(JSContext* /* unused */, JSObject* /* unused */)
+{
+  // If we're already on a worker workers are clearly enabled.
+  if (!NS_IsMainThread()) {
+    return true;
+  }
+
+  // If our caller is chrome, workers are always available.
+  if (nsContentUtils::IsCallerChrome()) {
+    return true;
+  }
+
+  // Else check the pref.
+  return Preferences::GetBool(PREF_WORKERS_ENABLED);
+}
+
+// static
+already_AddRefed<ChromeWorkerPrivate>
+ChromeWorkerPrivate::Constructor(const GlobalObject& aGlobal,
+                                 const nsAString& aScriptURL,
+                                 ErrorResult& aRv)
+{
+  return WorkerPrivate::Constructor(aGlobal, aScriptURL, true,
+                                    WorkerTypeDedicated, EmptyCString(),
+                                    nullptr, aRv)
+                                    .downcast<ChromeWorkerPrivate>();
+}
+
+// static
+bool
+ChromeWorkerPrivate::WorkerAvailable(JSContext* /* unused */, JSObject* /* unused */)
+{
+  // Chrome is always allowed to use workers, and content is never allowed to
+  // use ChromeWorker, so all we have to check is the caller.
+  return nsContentUtils::ThreadsafeIsCallerChrome();
+}
+
+// static
+already_AddRefed<WorkerPrivate>
+WorkerPrivate::Constructor(const GlobalObject& aGlobal,
+                           const nsAString& aScriptURL,
+                           bool aIsChromeWorker, WorkerType aWorkerType,
+                           const nsACString& aSharedWorkerName,
+                           LoadInfo* aLoadInfo, ErrorResult& aRv)
+{
+  WorkerPrivate* parent = NS_IsMainThread() ?
+                          nullptr :
+                          GetCurrentThreadWorkerPrivate();
+  if (parent) {
+    parent->AssertIsOnWorkerThread();
+  } else {
+    AssertIsOnMainThread();
+  }
+
+  JSContext* cx = aGlobal.GetContext();
+
+  MOZ_ASSERT_IF(aWorkerType == WorkerTypeShared,
+                !aSharedWorkerName.IsVoid());
+  MOZ_ASSERT_IF(aWorkerType != WorkerTypeShared,
+                aSharedWorkerName.IsEmpty());
+
+  Maybe<LoadInfo> stackLoadInfo;
+  if (!aLoadInfo) {
+    stackLoadInfo.construct();
+
+    nsresult rv = GetLoadInfo(cx, nullptr, parent, aScriptURL,
+                              aIsChromeWorker, stackLoadInfo.addr());
+    if (NS_FAILED(rv)) {
+      scriptloader::ReportLoadError(cx, aScriptURL, rv, !parent);
+      aRv.Throw(rv);
+      return nullptr;
+    }
+
+    aLoadInfo = stackLoadInfo.addr();
+  }
+
+  // NB: This has to be done before creating the WorkerPrivate, because it will
+  // attempt to use static variables that are initialized in the RuntimeService
+  // constructor.
+  RuntimeService* runtimeService;
+
+  if (!parent) {
+    runtimeService = RuntimeService::GetOrCreateService();
+    if (!runtimeService) {
+      JS_ReportError(cx, "Failed to create runtime service!");
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+  }
+  else {
+    runtimeService = RuntimeService::GetService();
+  }
+
+  MOZ_ASSERT(runtimeService);
+
+  nsRefPtr<WorkerPrivate> worker =
+    new WorkerPrivate(cx, parent, aScriptURL, aIsChromeWorker,
+                      aWorkerType, aSharedWorkerName, *aLoadInfo);
+
+  if (!runtimeService->RegisterWorker(cx, worker)) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return nullptr;
+  }
+
+  nsRefPtr<CompileScriptRunnable> compiler = new CompileScriptRunnable(worker);
+  if (!compiler->Dispatch(cx)) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return nullptr;
+  }
+
+  worker->mSelfRef = worker;
+
+  return worker.forget();
+}
+
+// static
+nsresult
+WorkerPrivate::GetLoadInfo(JSContext* aCx, nsPIDOMWindow* aWindow,
+                           WorkerPrivate* aParent, const nsAString& aScriptURL,
+                           bool aIsChromeWorker, LoadInfo* aLoadInfo)
+{
+  using namespace mozilla::dom::workers::scriptloader;
+
+  MOZ_ASSERT(aCx);
+
+  if (aWindow) {
+    AssertIsOnMainThread();
+  }
+
+  LoadInfo loadInfo;
+  nsresult rv;
+
+  if (aParent) {
+    aParent->AssertIsOnWorkerThread();
+
+    // If the parent is going away give up now.
+    Status parentStatus;
+    {
+      MutexAutoLock lock(aParent->mMutex);
+      parentStatus = aParent->mStatus;
+    }
+
+    if (parentStatus > Running) {
+      NS_WARNING("Cannot create child workers from the close handler!");
+      return NS_ERROR_FAILURE;
+    }
+
+    // StartAssignment() is used instead getter_AddRefs because, getter_AddRefs
+    // does QI in debug build and, if this worker runs in a child process,
+    // HttpChannelChild will crash because it's not thread-safe.
+    rv = ChannelFromScriptURLWorkerThread(aCx, aParent, aScriptURL,
+                                          loadInfo.mChannel.StartAssignment());
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Now that we've spun the loop there's no guarantee that our parent is
+    // still alive.  We may have received control messages initiating shutdown.
+    {
+      MutexAutoLock lock(aParent->mMutex);
+      parentStatus = aParent->mStatus;
+    }
+
+    if (parentStatus > Running) {
+      nsCOMPtr<nsIThread> mainThread;
+      if (NS_FAILED(NS_GetMainThread(getter_AddRefs(mainThread))) ||
+          NS_FAILED(NS_ProxyRelease(mainThread, loadInfo.mChannel))) {
+        NS_WARNING("Failed to proxy release of channel, leaking instead!");
+      }
+      return NS_ERROR_FAILURE;
+    }
+
+    loadInfo.mDomain = aParent->Domain();
+  } else {
+    AssertIsOnMainThread();
+
+    nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+    MOZ_ASSERT(ssm);
+
+    bool isChrome = nsContentUtils::IsCallerChrome();
+
+    // First check to make sure the caller has permission to make a privileged
+    // worker if they called the ChromeWorker/ChromeSharedWorker constructor.
+    if (aIsChromeWorker && !isChrome) {
+      return NS_ERROR_DOM_SECURITY_ERR;
+    }
+
+    // Chrome callers (whether ChromeWorker of Worker) always get the system
+    // principal here as they're allowed to load anything. The script loader may
+    // change the principal later depending on the script uri.
+    if (isChrome) {
+      rv = ssm->GetSystemPrincipal(getter_AddRefs(loadInfo.mPrincipal));
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    // See if we're being called from a window.
+    nsCOMPtr<nsPIDOMWindow> globalWindow = aWindow;
+    if (!globalWindow) {
+      nsCOMPtr<nsIScriptGlobalObject> scriptGlobal =
+        nsJSUtils::GetStaticScriptGlobal(JS::CurrentGlobalOrNull(aCx));
+      if (scriptGlobal) {
+        globalWindow = do_QueryInterface(scriptGlobal);
+        MOZ_ASSERT(globalWindow);
+      }
+    }
+
+    nsCOMPtr<nsIDocument> document;
+
+    if (globalWindow) {
+      // Only use the current inner window, and only use it if the caller can
+      // access it.
+      nsPIDOMWindow* outerWindow = globalWindow->GetOuterWindow();
+      if (outerWindow) {
+        loadInfo.mWindow = outerWindow->GetCurrentInnerWindow();
+      }
+
+      if (!loadInfo.mWindow ||
+          (globalWindow != loadInfo.mWindow &&
+            !nsContentUtils::CanCallerAccess(loadInfo.mWindow))) {
+        return NS_ERROR_DOM_SECURITY_ERR;
+      }
+
+      nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(loadInfo.mWindow);
+      MOZ_ASSERT(sgo);
+
+      loadInfo.mScriptContext = sgo->GetContext();
+      NS_ENSURE_TRUE(loadInfo.mScriptContext, NS_ERROR_FAILURE);
+
+      // If we're called from a window then we can dig out the principal and URI
+      // from the document.
+      document = loadInfo.mWindow->GetExtantDoc();
+      NS_ENSURE_TRUE(document, NS_ERROR_FAILURE);
+
+      loadInfo.mBaseURI = document->GetDocBaseURI();
+
+      // Use the document's NodePrincipal as our principal if we're not being
+      // called from chrome.
+      if (!loadInfo.mPrincipal) {
+        loadInfo.mPrincipal = document->NodePrincipal();
+        NS_ENSURE_TRUE(loadInfo.mPrincipal, NS_ERROR_FAILURE);
+
+        // We use the document's base domain to limit the number of workers
+        // each domain can create. For sandboxed documents, we use the domain
+        // of their first non-sandboxed document, walking up until we find
+        // one. If we can't find one, we fall back to using the GUID of the
+        // null principal as the base domain.
+        if (document->GetSandboxFlags() & SANDBOXED_ORIGIN) {
+          nsCOMPtr<nsIDocument> tmpDoc = document;
+          do {
+            tmpDoc = tmpDoc->GetParentDocument();
+          } while (tmpDoc && tmpDoc->GetSandboxFlags() & SANDBOXED_ORIGIN);
+
+          if (tmpDoc) {
+            // There was an unsandboxed ancestor, yay!
+            nsCOMPtr<nsIPrincipal> tmpPrincipal = tmpDoc->NodePrincipal();
+            rv = tmpPrincipal->GetBaseDomain(loadInfo.mDomain);
+            NS_ENSURE_SUCCESS(rv, rv);
+          } else {
+            // No unsandboxed ancestor, use our GUID.
+            rv = loadInfo.mPrincipal->GetBaseDomain(loadInfo.mDomain);
+            NS_ENSURE_SUCCESS(rv, rv);
+          }
+        } else {
+          // Document creating the worker is not sandboxed.
+          rv = loadInfo.mPrincipal->GetBaseDomain(loadInfo.mDomain);
+          NS_ENSURE_SUCCESS(rv, rv);
+        }
+      }
+
+      nsCOMPtr<nsIPermissionManager> permMgr =
+        do_GetService(NS_PERMISSIONMANAGER_CONTRACTID, &rv);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      uint32_t perm;
+      rv = permMgr->TestPermissionFromPrincipal(loadInfo.mPrincipal, "systemXHR",
+                                                &perm);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      loadInfo.mXHRParamsAllowed = perm == nsIPermissionManager::ALLOW_ACTION;
+    } else {
+      // Not a window
+      MOZ_ASSERT(isChrome);
+
+      // We're being created outside of a window. Need to figure out the script
+      // that is creating us in order for us to use relative URIs later on.
+      JS::AutoFilename fileName;
+      if (JS::DescribeScriptedCaller(aCx, &fileName)) {
+        // In most cases, fileName is URI. In a few other cases
+        // (e.g. xpcshell), fileName is a file path. Ideally, we would
+        // prefer testing whether fileName parses as an URI and fallback
+        // to file path in case of error, but Windows file paths have
+        // the interesting property that they can be parsed as bogus
+        // URIs (e.g. C:/Windows/Tmp is interpreted as scheme "C",
+        // hostname "Windows", path "Tmp"), which defeats this algorithm.
+        // Therefore, we adopt the opposite convention.
+        nsCOMPtr<nsIFile> scriptFile =
+          do_CreateInstance("@mozilla.org/file/local;1", &rv);
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+
+        rv = scriptFile->InitWithPath(NS_ConvertUTF8toUTF16(fileName.get()));
+        if (NS_SUCCEEDED(rv)) {
+          rv = NS_NewFileURI(getter_AddRefs(loadInfo.mBaseURI),
+                             scriptFile);
+        }
+        if (NS_FAILED(rv)) {
+          // As expected, fileName is not a path, so proceed with
+          // a uri.
+          rv = NS_NewURI(getter_AddRefs(loadInfo.mBaseURI),
+                         fileName.get());
+        }
+        if (NS_FAILED(rv)) {
+          return rv;
+        }
+      }
+      loadInfo.mXHRParamsAllowed = true;
+    }
+
+    MOZ_ASSERT(loadInfo.mPrincipal);
+    MOZ_ASSERT(isChrome || !loadInfo.mDomain.IsEmpty());
+
+    // XXXbent Use subject principal here instead of the one we already have?
+    nsCOMPtr<nsIPrincipal> subjectPrincipal = ssm->GetCxSubjectPrincipal(aCx);
+    MOZ_ASSERT(subjectPrincipal);
+
+    if (!nsContentUtils::GetContentSecurityPolicy(aCx,
+                                               getter_AddRefs(loadInfo.mCSP))) {
+      NS_WARNING("Failed to get CSP!");
+      return NS_ERROR_FAILURE;
+    }
+
+    if (loadInfo.mCSP) {
+      rv = loadInfo.mCSP->GetAllowsEval(&loadInfo.mReportCSPViolations,
+                                        &loadInfo.mEvalAllowed);
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      loadInfo.mEvalAllowed = true;
+      loadInfo.mReportCSPViolations = false;
+    }
+
+    rv = ChannelFromScriptURLMainThread(loadInfo.mPrincipal, loadInfo.mBaseURI,
+                                        document, aScriptURL,
+                                        getter_AddRefs(loadInfo.mChannel));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = NS_GetFinalChannelURI(loadInfo.mChannel,
+                               getter_AddRefs(loadInfo.mResolvedScriptURI));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  aLoadInfo->StealFrom(loadInfo);
+  return NS_OK;
+}
+
+void
+WorkerPrivate::DoRunLoop(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(mThread);
+
+  {
+    MutexAutoLock lock(mMutex);
+    mJSContext = aCx;
+
+    MOZ_ASSERT(mStatus == Pending);
+    mStatus = Running;
+  }
+
+  EnableMemoryReporter();
+
+  InitializeGCTimers();
+
+  Maybe<JSAutoCompartment> workerCompartment;
+
+  for (;;) {
+    // Workers lazily create a global object in CompileScriptRunnable. We need
+    // to enter the global's compartment as soon as it has been created.
+    if (workerCompartment.empty()) {
+      if (JSObject* global = js::DefaultObjectForContextOrNull(aCx)) {
+        workerCompartment.construct(aCx, global);
+      }
+    }
+
+    Status currentStatus;
+    bool normalRunnablesPending = false;
+
+    {
+      MutexAutoLock lock(mMutex);
+
+      while (mControlQueue.IsEmpty() &&
+             !(normalRunnablesPending = NS_HasPendingEvents(mThread))) {
+        WaitForWorkerEvents();
+      }
+
+      ProcessAllControlRunnablesLocked();
+
+      currentStatus = mStatus;
+    }
+
+    // If the close handler has finished and all features are done then we can
+    // kill this thread.
+    if (currentStatus != Running && !HasActiveFeatures()) {
+      if (mCloseHandlerFinished && currentStatus != Killing) {
+        if (!NotifyInternal(aCx, Killing)) {
+          JS_ReportPendingException(aCx);
+        }
+#ifdef DEBUG
+        {
+          MutexAutoLock lock(mMutex);
+          currentStatus = mStatus;
+        }
+        MOZ_ASSERT(currentStatus == Killing);
+#else
+        currentStatus = Killing;
+#endif
+      }
+
+      // If we're supposed to die then we should exit the loop.
+      if (currentStatus == Killing) {
+        ShutdownGCTimers();
+
+        DisableMemoryReporter();
+
+        {
+          MutexAutoLock lock(mMutex);
+
+          mStatus = Dead;
+          mJSContext = nullptr;
+        }
+
+        // After mStatus is set to Dead there can be no more
+        // WorkerControlRunnables so no need to lock here.
+        if (!mControlQueue.IsEmpty()) {
+          WorkerControlRunnable* runnable;
+          while (mControlQueue.Pop(runnable)) {
+            runnable->Cancel();
+            runnable->Release();
+          }
+        }
+
+        // Clear away our MessagePorts.
+        mWorkerPorts.Clear();
+
+        // Unroot the global
+        mScope = nullptr;
+
+        return;
+      }
+    }
+
+    // Nothing to do here if we don't have any runnables in the main queue.
+    if (!normalRunnablesPending) {
+      SetGCTimerMode(IdleTimer);
+      continue;
+    }
+
+    MOZ_ASSERT(NS_HasPendingEvents(mThread));
+
+    // Start the periodic GC timer if it is not already running.
+    SetGCTimerMode(PeriodicTimer);
+
+    // Process a single runnable from the main queue.
+    MOZ_ALWAYS_TRUE(NS_ProcessNextEvent(mThread, false));
+
+    if (NS_HasPendingEvents(mThread)) {
+      // Now *might* be a good time to GC. Let the JS engine make the decision.
+      if (!workerCompartment.empty()) {
+        JS_MaybeGC(aCx);
+      }
+    }
+    else {
+      // The normal event queue has been exhausted, cancel the periodic GC timer
+      // and schedule the idle GC timer.
+      SetGCTimerMode(IdleTimer);
+    }
+  }
+
+  MOZ_ASSUME_UNREACHABLE("Shouldn't get here!");
+}
+
+void
+WorkerPrivate::OnProcessNextEvent(uint32_t aRecursionDepth)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(aRecursionDepth);
+
+  // Normally we process control runnables in DoRunLoop or RunCurrentSyncLoop.
+  // However, it's possible that non-worker C++ could spin its own nested event
+  // loop, and in that case we must ensure that we continue to process control
+  // runnables here.
+  if (aRecursionDepth > 1 &&
+      mSyncLoopStack.Length() < aRecursionDepth - 1) {
+    ProcessAllControlRunnables();
+  }
+}
+
+void
+WorkerPrivate::AfterProcessNextEvent(uint32_t aRecursionDepth)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(aRecursionDepth);
+}
+
+void
+WorkerPrivate::InitializeGCTimers()
+{
+  AssertIsOnWorkerThread();
+
+  // We need a timer for GC. The basic plan is to run a non-shrinking GC
+  // periodically (PERIODIC_GC_TIMER_DELAY_SEC) while the worker is running.
+  // Once the worker goes idle we set a short (IDLE_GC_TIMER_DELAY_SEC) timer to
+  // run a shrinking GC. If the worker receives more messages then the short
+  // timer is canceled and the periodic timer resumes.
+  mGCTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
+  MOZ_ASSERT(mGCTimer);
+
+  nsRefPtr<GarbageCollectRunnable> runnable =
+    new GarbageCollectRunnable(this, false, false);
+  mPeriodicGCTimerTarget = new TimerThreadEventTarget(this, runnable);
+
+  runnable = new GarbageCollectRunnable(this, true, false);
+  mIdleGCTimerTarget = new TimerThreadEventTarget(this, runnable);
+
+  mPeriodicGCTimerRunning = false;
+  mIdleGCTimerRunning = false;
+}
+
+void
+WorkerPrivate::SetGCTimerMode(GCTimerMode aMode)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(mGCTimer);
+  MOZ_ASSERT(mPeriodicGCTimerTarget);
+  MOZ_ASSERT(mIdleGCTimerTarget);
+
+  if ((aMode == PeriodicTimer && mPeriodicGCTimerRunning) ||
+      (aMode == IdleTimer && mIdleGCTimerRunning)) {
+    return;
+  }
+
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(mGCTimer->Cancel()));
+
+  mPeriodicGCTimerRunning = false;
+  mIdleGCTimerRunning = false;
+
+  LOG(("Worker %p canceled GC timer because %s\n", this,
+       aMode == PeriodicTimer ?
+       "periodic" :
+       aMode == IdleTimer ? "idle" : "none"));
+
+  if (aMode == NoTimer) {
+    return;
+  }
+
+  MOZ_ASSERT(aMode == PeriodicTimer || aMode == IdleTimer);
+
+  nsIEventTarget* target;
+  uint32_t delay;
+  int16_t type;
+
+  if (aMode == PeriodicTimer) {
+    target = mPeriodicGCTimerTarget;
+    delay = PERIODIC_GC_TIMER_DELAY_SEC * 1000;
+    type = nsITimer::TYPE_REPEATING_SLACK;
+  }
+  else {
+    target = mIdleGCTimerTarget;
+    delay = IDLE_GC_TIMER_DELAY_SEC * 1000;
+    type = nsITimer::TYPE_ONE_SHOT;
+  }
+
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(mGCTimer->SetTarget(target)));
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(mGCTimer->InitWithFuncCallback(DummyCallback,
+                                                              nullptr, delay,
+                                                              type)));
+
+  if (aMode == PeriodicTimer) {
+    LOG(("Worker %p scheduled periodic GC timer\n", this));
+    mPeriodicGCTimerRunning = true;
+  }
+  else {
+    LOG(("Worker %p scheduled idle GC timer\n", this));
+    mIdleGCTimerRunning = true;
+  }
+}
+
+void
+WorkerPrivate::ShutdownGCTimers()
+{
+  AssertIsOnWorkerThread();
+
+  MOZ_ASSERT(mGCTimer);
+
+  // Always make sure the timer is canceled.
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(mGCTimer->Cancel()));
+
+  LOG(("Worker %p killed the GC timer\n", this));
+
+  mGCTimer = nullptr;
+  mPeriodicGCTimerTarget = nullptr;
+  mIdleGCTimerTarget = nullptr;
+  mPeriodicGCTimerRunning = false;
+  mIdleGCTimerRunning = false;
+}
+
+bool
+WorkerPrivate::InterruptCallback(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  bool mayContinue = true;
+  bool scheduledIdleGC = false;
+
+  for (;;) {
+    // Run all control events now.
+    mayContinue = ProcessAllControlRunnables();
+
+    bool maySuspend = mSuspended;
+    if (maySuspend) {
+      MutexAutoLock lock(mMutex);
+      maySuspend = mStatus <= Running;
+    }
+
+    if (!mayContinue || !maySuspend) {
+      break;
+    }
+
+    // Cancel the periodic GC timer here before suspending. The idle GC timer
+    // will clean everything up once it runs.
+    if (!scheduledIdleGC) {
+      SetGCTimerMode(IdleTimer);
+      scheduledIdleGC = true;
+    }
+
+    while ((mayContinue = MayContinueRunning())) {
+      MutexAutoLock lock(mMutex);
+      if (!mControlQueue.IsEmpty()) {
+        break;
+      }
+
+      WaitForWorkerEvents(PR_MillisecondsToInterval(RemainingRunTimeMS()));
+    }
+  }
+
+  if (!mayContinue) {
+    // We want only uncatchable exceptions here.
+    NS_ASSERTION(!JS_IsExceptionPending(aCx),
+                 "Should not have an exception set here!");
+    return false;
+  }
+
+  // Make sure the periodic timer gets turned back on here.
+  SetGCTimerMode(PeriodicTimer);
+
+  return true;
+}
+
+nsresult
+WorkerPrivate::IsOnCurrentThread(bool* aIsOnCurrentThread)
+{
+  // May be called on any thread!
+
+  MOZ_ASSERT(aIsOnCurrentThread);
+
+  nsCOMPtr<nsIThread> thread;
+  {
+    MutexAutoLock lock(mMutex);
+    thread = mThread;
+  }
+
+  if (!thread) {
+    NS_WARNING("Trying to test thread correctness after the worker has "
+               "released its thread!");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = thread->IsOnCurrentThread(aIsOnCurrentThread);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+void
+WorkerPrivate::ScheduleDeletion(WorkerRanOrNot aRanOrNot)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(mChildWorkers.IsEmpty());
+  MOZ_ASSERT(mSyncLoopStack.IsEmpty());
+
+  ClearMainEventQueue(aRanOrNot);
+
+  if (WorkerPrivate* parent = GetParent()) {
+    nsRefPtr<WorkerFinishedRunnable> runnable =
+      new WorkerFinishedRunnable(parent, this);
+    if (!runnable->Dispatch(nullptr)) {
+      NS_WARNING("Failed to dispatch runnable!");
+    }
+  }
+  else {
+    nsRefPtr<TopLevelWorkerFinishedRunnable> runnable =
+      new TopLevelWorkerFinishedRunnable(this);
+    if (NS_FAILED(NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL))) {
+      NS_WARNING("Failed to dispatch runnable!");
+    }
+  }
+}
+
+bool
+WorkerPrivate::BlockAndCollectRuntimeStats(JS::RuntimeStats* aRtStats)
+{
+  AssertIsOnMainThread();
+  mMutex.AssertCurrentThreadOwns();
+  NS_ASSERTION(aRtStats, "Null RuntimeStats!");
+
+  NS_ASSERTION(!mMemoryReporterRunning, "How can we get reentered here?!");
+
+  // This signals the worker that it should block itself as soon as possible.
+  mMemoryReporterRunning = true;
+
+  NS_ASSERTION(mJSContext, "This must never be null!");
+  JSRuntime* rt = JS_GetRuntime(mJSContext);
+
+  // If the worker is not already blocked (e.g. waiting for a worker event or
+  // currently in a ctypes call) then we need to trigger the interrupt
+  // callback to trap the worker.
+  if (!mBlockedForMemoryReporter) {
+    JS_RequestInterruptCallback(rt);
+
+    // Wait until the worker actually blocks.
+    while (!mBlockedForMemoryReporter) {
+      mMemoryReportCondVar.Wait();
+    }
+  }
+
+  bool succeeded = false;
+
+  // If mMemoryReporter is still set then we can do the actual report. Otherwise
+  // we're trying to shut down and we don't want to do anything but clean up.
+  if (mMemoryReporter) {
+    // Don't hold the lock while doing the actual report.
+    MutexAutoUnlock unlock(mMutex);
+    succeeded = JS::CollectRuntimeStats(rt, aRtStats, nullptr);
+  }
+
+  NS_ASSERTION(mMemoryReporterRunning, "This isn't possible!");
+  NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
+
+  // Tell the worker that it can now continue its execution.
+  mMemoryReporterRunning = false;
+
+  // The worker may be waiting so we must notify.
+  mMemoryReportCondVar.Notify();
+
+  return succeeded;
+}
+
+void
+WorkerPrivate::EnableMemoryReporter()
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(!mMemoryReporter);
+
+  // No need to lock here since the main thread can't race until we've
+  // successfully registered the reporter.
+  mMemoryReporter = new MemoryReporter(this);
+
+  if (NS_FAILED(RegisterWeakMemoryReporter(mMemoryReporter))) {
+    NS_WARNING("Failed to register memory reporter!");
+    // No need to lock here since a failed registration means our memory
+    // reporter can't start running. Just clean up.
+    mMemoryReporter = nullptr;
+  }
+}
+
+void
+WorkerPrivate::DisableMemoryReporter()
+{
+  AssertIsOnWorkerThread();
+
+  nsRefPtr<MemoryReporter> memoryReporter;
+  {
+    MutexAutoLock lock(mMutex);
+
+    // There is nothing to do here if the memory reporter was never successfully
+    // registered.
+    if (!mMemoryReporter) {
+      return;
+    }
+
+    // We don't need this set any longer. Swap it out so that we can unregister
+    // below.
+    mMemoryReporter.swap(memoryReporter);
+
+    // Next disable the memory reporter so that the main thread stops trying to
+    // signal us.
+    memoryReporter->Disable();
+
+    // If the memory reporter is waiting to start then we need to wait for it to
+    // finish.
+    if (mMemoryReporterRunning) {
+      NS_ASSERTION(!mBlockedForMemoryReporter,
+                   "Can't be blocked in more than one place at the same time!");
+      mBlockedForMemoryReporter = true;
+
+      // Tell the main thread that we're blocked.
+      mMemoryReportCondVar.Notify();
+
+      // Wait for it the main thread to finish. Since we swapped out
+      // mMemoryReporter above the main thread should respond quickly.
+      while (mMemoryReporterRunning) {
+        mMemoryReportCondVar.Wait();
+      }
+
+      NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
+      mBlockedForMemoryReporter = false;
+    }
+  }
+
+  // Finally unregister the memory reporter.
+  if (NS_FAILED(UnregisterWeakMemoryReporter(memoryReporter))) {
+    NS_WARNING("Failed to unregister memory reporter!");
+  }
+}
+
+void
+WorkerPrivate::WaitForWorkerEvents(PRIntervalTime aInterval)
+{
+  AssertIsOnWorkerThread();
+  mMutex.AssertCurrentThreadOwns();
+
+  NS_ASSERTION(!mBlockedForMemoryReporter,
+                "Can't be blocked in more than one place at the same time!");
+
+  // Let the main thread know that the worker is blocked and that memory
+  // reporting may proceed.
+  mBlockedForMemoryReporter = true;
+
+  // The main thread may be waiting so we must notify.
+  mMemoryReportCondVar.Notify();
+
+  // Now wait for an actual worker event.
+  mCondVar.Wait(aInterval);
+
+  // We've gotten some kind of signal but we can't continue until the memory
+  // reporter has finished. Wait again.
+  while (mMemoryReporterRunning) {
+    mMemoryReportCondVar.Wait();
+  }
+
+  NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
+
+  // No need to notify here as the main thread isn't watching for this state.
+  mBlockedForMemoryReporter = false;
+}
+
+bool
+WorkerPrivate::ProcessAllControlRunnablesLocked()
+{
+  AssertIsOnWorkerThread();
+  mMutex.AssertCurrentThreadOwns();
+
+  bool result = true;
+
+  for (;;) {
+    // Block here if the memory reporter is trying to run.
+    if (mMemoryReporterRunning) {
+      MOZ_ASSERT(!mBlockedForMemoryReporter);
+
+      // Let the main thread know that we've received the block request and
+      // that memory reporting may proceed.
+      mBlockedForMemoryReporter = true;
+
+      // The main thread is almost certainly waiting so we must notify here.
+      mMemoryReportCondVar.Notify();
+
+      // Wait for the memory report to finish.
+      while (mMemoryReporterRunning) {
+        mMemoryReportCondVar.Wait();
+      }
+
+      MOZ_ASSERT(mBlockedForMemoryReporter);
+
+      // No need to notify here as the main thread isn't watching for this
+      // state.
+      mBlockedForMemoryReporter = false;
+    }
+
+    WorkerControlRunnable* event;
+    if (!mControlQueue.Pop(event)) {
+      break;
+    }
+
+    MutexAutoUnlock unlock(mMutex);
+
+    MOZ_ASSERT(event);
+    if (NS_FAILED(static_cast<nsIRunnable*>(event)->Run())) {
+      result = false;
+    }
+
+    event->Release();
+  }
+
+  return result;
+}
+
+void
+WorkerPrivate::ClearMainEventQueue(WorkerRanOrNot aRanOrNot)
+{
+  AssertIsOnWorkerThread();
+
+  MOZ_ASSERT(!mCancelAllPendingRunnables);
+  mCancelAllPendingRunnables = true;
+
+  if (WorkerNeverRan == aRanOrNot) {
+    for (uint32_t count = mPreStartRunnables.Length(), index = 0;
+         index < count;
+         index++) {
+      nsRefPtr<WorkerRunnable> runnable = mPreStartRunnables[index].forget();
+      static_cast<nsIRunnable*>(runnable.get())->Run();
+    }
+  } else {
+    nsIThread* currentThread = NS_GetCurrentThread();
+    MOZ_ASSERT(currentThread);
+
+    NS_ProcessPendingEvents(currentThread);
+    MOZ_ASSERT(!NS_HasPendingEvents(currentThread));
+  }
+
+  MOZ_ASSERT(mCancelAllPendingRunnables);
+  mCancelAllPendingRunnables = false;
+}
+
+uint32_t
+WorkerPrivate::RemainingRunTimeMS() const
+{
+  if (mKillTime.IsNull()) {
+    return UINT32_MAX;
+  }
+  TimeDuration runtime = mKillTime - TimeStamp::Now();
+  double ms = runtime > TimeDuration(0) ? runtime.ToMilliseconds() : 0;
+  return ms > double(UINT32_MAX) ? UINT32_MAX : uint32_t(ms);
+}
+
+bool
+WorkerPrivate::SuspendInternal(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(!mSuspended, "Already suspended!");
+
+  mSuspended = true;
+  return true;
+}
+
+bool
+WorkerPrivate::ResumeInternal(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(mSuspended, "Not yet suspended!");
+
+  mSuspended = false;
+  return true;
+}
+
+void
+WorkerPrivate::TraceTimeouts(const TraceCallbacks& aCallbacks,
+                             void* aClosure) const
+{
+  AssertIsOnWorkerThread();
+
+  for (uint32_t index = 0; index < mTimeouts.Length(); index++) {
+    TimeoutInfo* info = mTimeouts[index];
+
+    if (info->mTimeoutCallable.isUndefined()) {
+      continue;
+    }
+
+    aCallbacks.Trace(&info->mTimeoutCallable, "mTimeoutCallable", aClosure);
+    for (uint32_t index2 = 0; index2 < info->mExtraArgVals.Length(); index2++) {
+      aCallbacks.Trace(&info->mExtraArgVals[index2], "mExtraArgVals[i]", aClosure);
+    }
+  }
+}
+
+bool
+WorkerPrivate::ModifyBusyCountFromWorker(JSContext* aCx, bool aIncrease)
+{
+  AssertIsOnWorkerThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    // If we're in shutdown then the busy count is no longer being considered so
+    // just return now.
+    if (mStatus >= Killing) {
+      return true;
+    }
+  }
+
+  nsRefPtr<ModifyBusyCountRunnable> runnable =
+    new ModifyBusyCountRunnable(this, aIncrease);
+  return runnable->Dispatch(aCx);
+}
+
+bool
+WorkerPrivate::AddChildWorker(JSContext* aCx, ParentType* aChildWorker)
+{
+  AssertIsOnWorkerThread();
+
+#ifdef DEBUG
+  {
+    Status currentStatus;
+    {
+      MutexAutoLock lock(mMutex);
+      currentStatus = mStatus;
+    }
+
+    MOZ_ASSERT(currentStatus == Running);
+  }
+#endif
+
+  NS_ASSERTION(!mChildWorkers.Contains(aChildWorker),
+               "Already know about this one!");
+  mChildWorkers.AppendElement(aChildWorker);
+
+  return mChildWorkers.Length() == 1 ?
+         ModifyBusyCountFromWorker(aCx, true) :
+         true;
+}
+
+void
+WorkerPrivate::RemoveChildWorker(JSContext* aCx, ParentType* aChildWorker)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(mChildWorkers.Contains(aChildWorker),
+               "Didn't know about this one!");
+  mChildWorkers.RemoveElement(aChildWorker);
+
+  if (mChildWorkers.IsEmpty() && !ModifyBusyCountFromWorker(aCx, false)) {
+    NS_WARNING("Failed to modify busy count!");
+  }
+}
+
+bool
+WorkerPrivate::AddFeature(JSContext* aCx, WorkerFeature* aFeature)
+{
+  AssertIsOnWorkerThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mStatus >= Canceling) {
+      return false;
+    }
+  }
+
+  NS_ASSERTION(!mFeatures.Contains(aFeature), "Already know about this one!");
+  mFeatures.AppendElement(aFeature);
+
+  return mFeatures.Length() == 1 ?
+         ModifyBusyCountFromWorker(aCx, true) :
+         true;
+}
+
+void
+WorkerPrivate::RemoveFeature(JSContext* aCx, WorkerFeature* aFeature)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(mFeatures.Contains(aFeature), "Didn't know about this one!");
+  mFeatures.RemoveElement(aFeature);
+
+  if (mFeatures.IsEmpty() && !ModifyBusyCountFromWorker(aCx, false)) {
+    NS_WARNING("Failed to modify busy count!");
+  }
+}
+
+void
+WorkerPrivate::NotifyFeatures(JSContext* aCx, Status aStatus)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(aStatus > Running, "Bad status!");
+
+  if (aStatus >= Closing) {
+    CancelAllTimeouts(aCx);
+  }
+
+  nsAutoTArray<WorkerFeature*, 30> features;
+  features.AppendElements(mFeatures);
+
+  for (uint32_t index = 0; index < features.Length(); index++) {
+    if (!features[index]->Notify(aCx, aStatus)) {
+      NS_WARNING("Failed to notify feature!");
+    }
+  }
+
+  nsAutoTArray<ParentType*, 10> children;
+  children.AppendElements(mChildWorkers);
+
+  for (uint32_t index = 0; index < children.Length(); index++) {
+    if (!children[index]->Notify(aCx, aStatus)) {
+      NS_WARNING("Failed to notify child worker!");
+    }
+  }
+}
+
+void
+WorkerPrivate::CancelAllTimeouts(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  if (mTimerRunning) {
+    NS_ASSERTION(mTimer, "Huh?!");
+    NS_ASSERTION(!mTimeouts.IsEmpty(), "Huh?!");
+
+    if (NS_FAILED(mTimer->Cancel())) {
+      NS_WARNING("Failed to cancel timer!");
+    }
+
+    for (uint32_t index = 0; index < mTimeouts.Length(); index++) {
+      mTimeouts[index]->mCanceled = true;
+    }
+
+    if (!RunExpiredTimeouts(aCx)) {
+      JS_ReportPendingException(aCx);
+    }
+
+    mTimerRunning = false;
+  }
+#ifdef DEBUG
+  else if (!mRunningExpiredTimeouts) {
+    NS_ASSERTION(mTimeouts.IsEmpty(), "Huh?!");
+  }
+#endif
+
+  mTimer = nullptr;
+}
+
+already_AddRefed<nsIEventTarget>
+WorkerPrivate::CreateNewSyncLoop()
+{
+  AssertIsOnWorkerThread();
+
+  nsCOMPtr<nsIThreadInternal> thread = do_QueryInterface(NS_GetCurrentThread());
+  MOZ_ASSERT(thread);
+
+  nsCOMPtr<nsIEventTarget> realEventTarget;
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(thread->PushEventQueue(
+                                             getter_AddRefs(realEventTarget))));
+
+  nsRefPtr<EventTarget> workerEventTarget =
+    new EventTarget(this, realEventTarget);
+
+  {
+    // Modifications must be protected by mMutex in DEBUG builds, see comment
+    // about mSyncLoopStack in WorkerPrivate.h.
+#ifdef DEBUG
+    MutexAutoLock lock(mMutex);
+#endif
+
+    mSyncLoopStack.AppendElement(new SyncLoopInfo(workerEventTarget));
+  }
+
+  return workerEventTarget.forget();
+}
+
+bool
+WorkerPrivate::RunCurrentSyncLoop()
+{
+  AssertIsOnWorkerThread();
+
+  JSContext* cx = GetJSContext();
+  MOZ_ASSERT(cx);
+
+  // This should not change between now and the time we finish running this sync
+  // loop.
+  uint32_t currentLoopIndex = mSyncLoopStack.Length() - 1;
+
+  SyncLoopInfo* loopInfo = mSyncLoopStack[currentLoopIndex];
+
+  MOZ_ASSERT(loopInfo);
+  MOZ_ASSERT(!loopInfo->mHasRun);
+  MOZ_ASSERT(!loopInfo->mCompleted);
+
+#ifdef DEBUG
+  loopInfo->mHasRun = true;
+#endif
+
+  nsCOMPtr<nsIThreadInternal> thread = do_QueryInterface(mThread);
+  MOZ_ASSERT(thread);
+
+  while (!loopInfo->mCompleted) {
+    bool normalRunnablesPending = false;
+
+    // Don't block with the periodic GC timer running.
+    if (!NS_HasPendingEvents(thread)) {
+      SetGCTimerMode(IdleTimer);
+    }
+
+    // Wait for something to do.
+    {
+      MutexAutoLock lock(mMutex);
+
+      for (;;) {
+        while (mControlQueue.IsEmpty() &&
+               !normalRunnablesPending &&
+               !(normalRunnablesPending = NS_HasPendingEvents(thread))) {
+          WaitForWorkerEvents();
+        }
+
+        ProcessAllControlRunnablesLocked();
+
+        // NB: If we processed a NotifyRunnable, we might have run non-control
+        // runnables, one of which may have shut down the sync loop.
+        if (normalRunnablesPending || loopInfo->mCompleted) {
+          break;
+        }
+      }
+    }
+
+    if (normalRunnablesPending) {
+      // Make sure the periodic timer is running before we continue.
+      SetGCTimerMode(PeriodicTimer);
+
+      MOZ_ALWAYS_TRUE(NS_ProcessNextEvent(thread, false));
+
+      // Now *might* be a good time to GC. Let the JS engine make the decision.
+      JS_MaybeGC(cx);
+    }
+  }
+
+  // Make sure that the stack didn't change underneath us.
+  MOZ_ASSERT(mSyncLoopStack[currentLoopIndex] == loopInfo);
+
+  return DestroySyncLoop(currentLoopIndex);
+}
+
+bool
+WorkerPrivate::DestroySyncLoop(uint32_t aLoopIndex, nsIThreadInternal* aThread)
+{
+  MOZ_ASSERT(!mSyncLoopStack.IsEmpty());
+  MOZ_ASSERT(mSyncLoopStack.Length() - 1 == aLoopIndex);
+
+  if (!aThread) {
+    nsCOMPtr<nsIThreadInternal> thread = do_QueryInterface(mThread);
+    MOZ_ASSERT(thread);
+
+    aThread = thread.get();
+  }
+
+  // We're about to delete the loop, stash its event target and result.
+  SyncLoopInfo* loopInfo = mSyncLoopStack[aLoopIndex];
+  nsIEventTarget* nestedEventTarget =
+    loopInfo->mEventTarget->GetWeakNestedEventTarget();
+  MOZ_ASSERT(nestedEventTarget);
+
+  bool result = loopInfo->mResult;
+
+  {
+    // Modifications must be protected by mMutex in DEBUG builds, see comment
+    // about mSyncLoopStack in WorkerPrivate.h.
+#ifdef DEBUG
+    MutexAutoLock lock(mMutex);
+#endif
+
+    // This will delete |loopInfo|!
+    mSyncLoopStack.RemoveElementAt(aLoopIndex);
+  }
+
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(aThread->PopEventQueue(nestedEventTarget)));
+
+  return result;
+}
+
+void
+WorkerPrivate::StopSyncLoop(nsIEventTarget* aSyncLoopTarget, bool aResult)
+{
+  AssertIsOnWorkerThread();
+  AssertValidSyncLoop(aSyncLoopTarget);
+
+  MOZ_ASSERT(!mSyncLoopStack.IsEmpty());
+
+  for (uint32_t index = mSyncLoopStack.Length(); index > 0; index--) {
+    nsAutoPtr<SyncLoopInfo>& loopInfo = mSyncLoopStack[index - 1];
+    MOZ_ASSERT(loopInfo);
+    MOZ_ASSERT(loopInfo->mEventTarget);
+
+    if (loopInfo->mEventTarget == aSyncLoopTarget) {
+      // Can't assert |loop->mHasRun| here because dispatch failures can cause
+      // us to bail out early.
+      MOZ_ASSERT(!loopInfo->mCompleted);
+
+      loopInfo->mResult = aResult;
+      loopInfo->mCompleted = true;
+
+      loopInfo->mEventTarget->Disable();
+
+      return;
+    }
+
+    MOZ_ASSERT(!SameCOMIdentity(loopInfo->mEventTarget, aSyncLoopTarget));
+  }
+
+  MOZ_CRASH("Unknown sync loop!");
+}
+
+#ifdef DEBUG
+void
+WorkerPrivate::AssertValidSyncLoop(nsIEventTarget* aSyncLoopTarget)
+{
+  MOZ_ASSERT(aSyncLoopTarget);
+
+  EventTarget* workerTarget;
+  nsresult rv =
+    aSyncLoopTarget->QueryInterface(kDEBUGWorkerEventTargetIID,
+                                    reinterpret_cast<void**>(&workerTarget));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_ASSERT(workerTarget);
+
+  bool valid = false;
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    for (uint32_t index = 0; index < mSyncLoopStack.Length(); index++) {
+      nsAutoPtr<SyncLoopInfo>& loopInfo = mSyncLoopStack[index];
+      MOZ_ASSERT(loopInfo);
+      MOZ_ASSERT(loopInfo->mEventTarget);
+
+      if (loopInfo->mEventTarget == aSyncLoopTarget) {
+        valid = true;
+        break;
+      }
+
+      MOZ_ASSERT(!SameCOMIdentity(loopInfo->mEventTarget, aSyncLoopTarget));
+    }
+  }
+
+  MOZ_ASSERT(valid);
+}
+#endif
+
+void
+WorkerPrivate::PostMessageToParentInternal(
+                            JSContext* aCx,
+                            JS::Handle<JS::Value> aMessage,
+                            const Optional<Sequence<JS::Value>>& aTransferable,
+                            bool aToMessagePort,
+                            uint64_t aMessagePortSerial,
+                            ErrorResult& aRv)
+{
+  AssertIsOnWorkerThread();
+
+  JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
+  if (aTransferable.WasPassed()) {
+    const Sequence<JS::Value>& realTransferable = aTransferable.Value();
+
+    // The input sequence only comes from the generated bindings code, which
+    // ensures it is rooted.
+    JS::HandleValueArray elements =
+      JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
+                                               realTransferable.Elements());
+
+    JSObject* array = JS_NewArrayObject(aCx, elements);
+    if (!array) {
+      aRv = NS_ERROR_OUT_OF_MEMORY;
+      return;
+    }
+    transferable.setObject(*array);
+  }
+
+  JSStructuredCloneCallbacks* callbacks =
+    IsChromeWorker() ?
+    &gChromeWorkerStructuredCloneCallbacks :
+    &gWorkerStructuredCloneCallbacks;
+
+  nsTArray<nsCOMPtr<nsISupports>> clonedObjects;
+
+  JSAutoStructuredCloneBuffer buffer;
+  if (!buffer.write(aCx, aMessage, transferable, callbacks, &clonedObjects)) {
+    aRv = NS_ERROR_DOM_DATA_CLONE_ERR;
+    return;
+  }
+
+  nsRefPtr<MessageEventRunnable> runnable =
+    new MessageEventRunnable(this,
+                             WorkerRunnable::ParentThreadUnchangedBusyCount,
+                             Move(buffer), clonedObjects, aToMessagePort,
+                             aMessagePortSerial);
+  if (!runnable->Dispatch(aCx)) {
+    aRv = NS_ERROR_FAILURE;
+  }
+}
+
+void
+WorkerPrivate::PostMessageToParentMessagePort(
+                             JSContext* aCx,
+                             uint64_t aMessagePortSerial,
+                             JS::Handle<JS::Value> aMessage,
+                             const Optional<Sequence<JS::Value>>& aTransferable,
+                             ErrorResult& aRv)
+{
+  AssertIsOnWorkerThread();
+
+  if (!mWorkerPorts.GetWeak(aMessagePortSerial)) {
+    // This port has been closed from the main thread. There's no point in
+    // sending this message so just bail.
+    return;
+  }
+
+  PostMessageToParentInternal(aCx, aMessage, aTransferable, true,
+                              aMessagePortSerial, aRv);
+}
+
+bool
+WorkerPrivate::NotifyInternal(JSContext* aCx, Status aStatus)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(aStatus > Running && aStatus < Dead, "Bad status!");
+
+  nsRefPtr<EventTarget> eventTarget;
+
+  // Save the old status and set the new status.
+  Status previousStatus;
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (mStatus >= aStatus) {
+      MOZ_ASSERT(!mEventTarget);
+      return true;
+    }
+
+    previousStatus = mStatus;
+    mStatus = aStatus;
+
+    mEventTarget.swap(eventTarget);
+  }
+
+  // Now that mStatus > Running, no-one can create a new WorkerEventTarget or
+  // WorkerCrossThreadDispatcher if we don't already have one.
+  if (eventTarget) {
+    // Since we'll no longer process events, make sure we no longer allow anyone
+    // to post them. We have to do this without mMutex held, since our mutex
+    // must be acquired *after* the WorkerEventTarget's mutex when they're both
+    // held.
+    eventTarget->Disable();
+    eventTarget = nullptr;
+  }
+
+  if (mCrossThreadDispatcher) {
+    // Since we'll no longer process events, make sure we no longer allow
+    // anyone to post them. We have to do this without mMutex held, since our
+    // mutex must be acquired *after* mCrossThreadDispatcher's mutex when
+    // they're both held.
+    mCrossThreadDispatcher->Forget();
+    mCrossThreadDispatcher = nullptr;
+  }
+
+  MOZ_ASSERT(previousStatus != Pending);
+
+  MOZ_ASSERT(previousStatus >= Canceling || mKillTime.IsNull());
+
+  // Let all our features know the new status.
+  NotifyFeatures(aCx, aStatus);
+
+  // If this is the first time our status has changed then we need to clear the
+  // main event queue.
+  if (previousStatus == Running) {
+    ClearMainEventQueue(WorkerRan);
+  }
+
+  // If we've run the close handler, we don't need to do anything else.
+  if (mCloseHandlerFinished) {
+    return true;
+  }
+
+  // If the worker script never ran, or failed to compile, we don't need to do
+  // anything else, except pretend that we ran the close handler.
+  if (!JS::CurrentGlobalOrNull(aCx)) {
+    mCloseHandlerStarted = true;
+    mCloseHandlerFinished = true;
+    return true;
+  }
+
+  // If this is the first time our status has changed we also need to schedule
+  // the close handler unless we're being shut down.
+  if (previousStatus == Running && aStatus != Killing) {
+    MOZ_ASSERT(!mCloseHandlerStarted && !mCloseHandlerFinished);
+
+    nsRefPtr<CloseEventRunnable> closeRunnable = new CloseEventRunnable(this);
+    MOZ_ALWAYS_TRUE(NS_SUCCEEDED(NS_DispatchToCurrentThread(closeRunnable)));
+  }
+
+  if (aStatus == Closing) {
+    // Notify parent to stop sending us messages and balance our busy count.
+    nsRefPtr<CloseRunnable> runnable = new CloseRunnable(this);
+    if (!runnable->Dispatch(aCx)) {
+      return false;
+    }
+
+    // Don't abort the script.
+    return true;
+  }
+
+  if (aStatus == Terminating) {
+    // Only abort the script if we're not yet running the close handler.
+    return mCloseHandlerStarted;
+  }
+
+  if (aStatus == Canceling) {
+    // We need to enforce a timeout on the close handler.
+    MOZ_ASSERT(previousStatus >= Running && previousStatus <= Terminating);
+
+    uint32_t killSeconds = IsChromeWorker() ?
+      RuntimeService::GetChromeCloseHandlerTimeoutSeconds() :
+      RuntimeService::GetContentCloseHandlerTimeoutSeconds();
+
+    if (killSeconds) {
+      mKillTime = TimeStamp::Now() + TimeDuration::FromSeconds(killSeconds);
+
+      if (!mCloseHandlerFinished && !ScheduleKillCloseEventRunnable(aCx)) {
+        return false;
+      }
+    }
+
+    // Only abort the script if we're not yet running the close handler.
+    return mCloseHandlerStarted;
+  }
+
+  MOZ_ASSERT(aStatus == Killing);
+
+  mKillTime = TimeStamp::Now();
+
+  if (mCloseHandlerStarted && !mCloseHandlerFinished) {
+    ScheduleKillCloseEventRunnable(aCx);
+  }
+
+  // Always abort the script.
+  return false;
+}
+
+bool
+WorkerPrivate::ScheduleKillCloseEventRunnable(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(!mKillTime.IsNull());
+
+  nsRefPtr<KillCloseEventRunnable> killCloseEventRunnable =
+    new KillCloseEventRunnable(this);
+  if (!killCloseEventRunnable->SetTimeout(aCx, RemainingRunTimeMS())) {
+    return false;
+  }
+
+  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(NS_DispatchToCurrentThread(
+                                                      killCloseEventRunnable)));
+
+  return true;
+}
+
+void
+WorkerPrivate::ReportError(JSContext* aCx, const char* aMessage,
+                           JSErrorReport* aReport)
+{
+  AssertIsOnWorkerThread();
+
+  if (!MayContinueRunning() || mErrorHandlerRecursionCount == 2) {
+    return;
+  }
+
+  NS_ASSERTION(mErrorHandlerRecursionCount == 0 ||
+               mErrorHandlerRecursionCount == 1,
+               "Bad recursion logic!");
+
+  JS_ClearPendingException(aCx);
+
+  nsString message, filename, line;
+  uint32_t lineNumber, columnNumber, flags, errorNumber;
+
+  if (aReport) {
+    // ErrorEvent objects don't have a |name| field the way ES |Error| objects
+    // do. Traditionally (and mostly by accident), the |message| field of
+    // ErrorEvent has corresponded to |Name: Message| of the original Error
+    // object. Things have been cleaned up in the JS engine, so now we need to
+    // format this string explicitly.
+    JS::Rooted<JSString*> messageStr(aCx,
+                                     js::ErrorReportToString(aCx, aReport));
+    if (messageStr) {
+      nsDependentJSString depStr;
+      if (depStr.init(aCx, messageStr)) {
+        message = depStr;
+      }
+    }
+    filename = NS_ConvertUTF8toUTF16(aReport->filename);
+    line = aReport->uclinebuf;
+    lineNumber = aReport->lineno;
+    columnNumber = aReport->uctokenptr - aReport->uclinebuf;
+    flags = aReport->flags;
+    errorNumber = aReport->errorNumber;
+  }
+  else {
+    lineNumber = columnNumber = errorNumber = 0;
+    flags = nsIScriptError::errorFlag | nsIScriptError::exceptionFlag;
+  }
+
+  if (message.IsEmpty()) {
+    message = NS_ConvertUTF8toUTF16(aMessage);
+  }
+
+  mErrorHandlerRecursionCount++;
+
+  // Don't want to run the scope's error handler if this is a recursive error or
+  // if there was an error in the close handler or if we ran out of memory.
+  bool fireAtScope = mErrorHandlerRecursionCount == 1 &&
+                     !mCloseHandlerStarted &&
+                     errorNumber != JSMSG_OUT_OF_MEMORY;
+
+  if (!ReportErrorRunnable::ReportError(aCx, this, fireAtScope, nullptr, message,
+                                        filename, line, lineNumber,
+                                        columnNumber, flags, errorNumber, 0)) {
+    JS_ReportPendingException(aCx);
+  }
+
+  mErrorHandlerRecursionCount--;
+}
+
+int32_t
+WorkerPrivate::SetTimeout(JSContext* aCx,
+                          Function* aHandler,
+                          const nsAString& aStringHandler,
+                          int32_t aTimeout,
+                          const Sequence<JS::Value>& aArguments,
+                          bool aIsInterval,
+                          ErrorResult& aRv)
+{
+  AssertIsOnWorkerThread();
+
+  const int32_t timerId = mNextTimeoutId++;
+
+  Status currentStatus;
+  {
+    MutexAutoLock lock(mMutex);
+    currentStatus = mStatus;
+  }
+
+  // It's a script bug if setTimeout/setInterval are called from a close handler
+  // so throw an exception.
+  if (currentStatus == Closing) {
+    JS_ReportError(aCx, "Cannot schedule timeouts from the close handler!");
+  }
+
+  // If the worker is trying to call setTimeout/setInterval and the parent
+  // thread has initiated the close process then just silently fail.
+  if (currentStatus >= Closing) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return 0;
+  }
+
+  nsAutoPtr<TimeoutInfo> newInfo(new TimeoutInfo());
+  newInfo->mIsInterval = aIsInterval;
+  newInfo->mId = timerId;
+
+  if (MOZ_UNLIKELY(timerId == INT32_MAX)) {
+    NS_WARNING("Timeout ids overflowed!");
+    mNextTimeoutId = 1;
+  }
+
+  // Take care of the main argument.
+  if (aHandler) {
+    newInfo->mTimeoutCallable = JS::ObjectValue(*aHandler->Callable());
+  }
+  else if (!aStringHandler.IsEmpty()) {
+    newInfo->mTimeoutString = aStringHandler;
+  }
+  else {
+    JS_ReportError(aCx, "Useless %s call (missing quotes around argument?)",
+                   aIsInterval ? "setInterval" : "setTimeout");
+    return 0;
+  }
+
+  // See if any of the optional arguments were passed.
+  aTimeout = std::max(0, aTimeout);
+  newInfo->mInterval = TimeDuration::FromMilliseconds(aTimeout);
+
+  uint32_t argc = aArguments.Length();
+  if (argc && !newInfo->mTimeoutCallable.isUndefined()) {
+    nsTArray<JS::Heap<JS::Value>> extraArgVals(argc);
+    for (uint32_t index = 0; index < argc; index++) {
+      extraArgVals.AppendElement(aArguments[index]);
+    }
+    newInfo->mExtraArgVals.SwapElements(extraArgVals);
+  }
+
+  newInfo->mTargetTime = TimeStamp::Now() + newInfo->mInterval;
+
+  if (!newInfo->mTimeoutString.IsEmpty()) {
+    const char* filenameChars;
+    uint32_t lineNumber;
+    if (nsJSUtils::GetCallingLocation(aCx, &filenameChars, &lineNumber)) {
+      newInfo->mFilename = filenameChars;
+      newInfo->mLineNumber = lineNumber;
+    }
+    else {
+      NS_WARNING("Failed to get calling location!");
+    }
+  }
+
+  nsAutoPtr<TimeoutInfo>* insertedInfo =
+    mTimeouts.InsertElementSorted(newInfo.forget(), GetAutoPtrComparator(mTimeouts));
+
+  // If the timeout we just made is set to fire next then we need to update the
+  // timer.
+  if (insertedInfo == mTimeouts.Elements()) {
+    nsresult rv;
+
+    if (!mTimer) {
+      nsCOMPtr<nsITimer> timer = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
+      if (NS_FAILED(rv)) {
+        aRv.Throw(rv);
+        return 0;
+      }
+
+      nsRefPtr<TimerRunnable> runnable = new TimerRunnable(this);
+
+      nsRefPtr<TimerThreadEventTarget> target =
+        new TimerThreadEventTarget(this, runnable);
+
+      rv = timer->SetTarget(target);
+      if (NS_FAILED(rv)) {
+        aRv.Throw(rv);
+        return 0;
+      }
+
+      timer.swap(mTimer);
+    }
+
+    if (!mTimerRunning) {
+      if (!ModifyBusyCountFromWorker(aCx, true)) {
+        aRv.Throw(NS_ERROR_FAILURE);
+        return 0;
+      }
+      mTimerRunning = true;
+    }
+
+    if (!RescheduleTimeoutTimer(aCx)) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return 0;
+    }
+  }
+
+  return timerId;
+}
+
+void
+WorkerPrivate::ClearTimeout(int32_t aId)
+{
+  AssertIsOnWorkerThread();
+
+  if (!mTimeouts.IsEmpty()) {
+    NS_ASSERTION(mTimerRunning, "Huh?!");
+
+    for (uint32_t index = 0; index < mTimeouts.Length(); index++) {
+      nsAutoPtr<TimeoutInfo>& info = mTimeouts[index];
+      if (info->mId == aId) {
+        info->mCanceled = true;
+        break;
+      }
+    }
+  }
+}
+
+bool
+WorkerPrivate::RunExpiredTimeouts(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  // We may be called recursively (e.g. close() inside a timeout) or we could
+  // have been canceled while this event was pending, bail out if there is
+  // nothing to do.
+  if (mRunningExpiredTimeouts || !mTimerRunning) {
+    return true;
+  }
+
+  NS_ASSERTION(mTimer, "Must have a timer!");
+  NS_ASSERTION(!mTimeouts.IsEmpty(), "Should have some work to do!");
+
+  bool retval = true;
+
+  AutoPtrComparator<TimeoutInfo> comparator = GetAutoPtrComparator(mTimeouts);
+  JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx));
+
+  // We want to make sure to run *something*, even if the timer fired a little
+  // early. Fudge the value of now to at least include the first timeout.
+  const TimeStamp now = std::max(TimeStamp::Now(), mTimeouts[0]->mTargetTime);
+
+  nsAutoTArray<TimeoutInfo*, 10> expiredTimeouts;
+  for (uint32_t index = 0; index < mTimeouts.Length(); index++) {
+    nsAutoPtr<TimeoutInfo>& info = mTimeouts[index];
+    if (info->mTargetTime > now) {
+      break;
+    }
+    expiredTimeouts.AppendElement(info);
+  }
+
+  // Guard against recursion.
+  mRunningExpiredTimeouts = true;
+
+  // Run expired timeouts.
+  for (uint32_t index = 0; index < expiredTimeouts.Length(); index++) {
+    TimeoutInfo*& info = expiredTimeouts[index];
+
+    if (info->mCanceled) {
+      continue;
+    }
+
+    // Always call JS_ReportPendingException if something fails, and if
+    // JS_ReportPendingException returns false (i.e. uncatchable exception) then
+    // break out of the loop.
+
+    if (!info->mTimeoutCallable.isUndefined()) {
+      JS::Rooted<JS::Value> rval(aCx);
+      JS::HandleValueArray args =
+        JS::HandleValueArray::fromMarkedLocation(info->mExtraArgVals.Length(),
+                                                 info->mExtraArgVals.Elements()->address());
+      JS::Rooted<JS::Value> callable(aCx, info->mTimeoutCallable);
+      if (!JS_CallFunctionValue(aCx, global, callable, args, &rval) &&
+          !JS_ReportPendingException(aCx)) {
+        retval = false;
+        break;
+      }
+    }
+    else {
+      nsString expression = info->mTimeoutString;
+
+      JS::CompileOptions options(aCx);
+      options.setFileAndLine(info->mFilename.get(), info->mLineNumber);
+
+      if ((expression.IsEmpty() ||
+           !JS::Evaluate(aCx, global, options, expression.get(), expression.Length())) &&
+          !JS_ReportPendingException(aCx)) {
+        retval = false;
+        break;
+      }
+    }
+
+    NS_ASSERTION(mRunningExpiredTimeouts, "Someone changed this!");
+  }
+
+  // No longer possible to be called recursively.
+  mRunningExpiredTimeouts = false;
+
+  // Now remove canceled and expired timeouts from the main list.
+  // NB: The timeouts present in expiredTimeouts must have the same order
+  // with respect to each other in mTimeouts.  That is, mTimeouts is just
+  // expiredTimeouts with extra elements inserted.  There may be unexpired
+  // timeouts that have been inserted between the expired timeouts if the
+  // timeout event handler called setTimeout/setInterval.
+  for (uint32_t index = 0, expiredTimeoutIndex = 0,
+       expiredTimeoutLength = expiredTimeouts.Length();
+       index < mTimeouts.Length(); ) {
+    nsAutoPtr<TimeoutInfo>& info = mTimeouts[index];
+    if ((expiredTimeoutIndex < expiredTimeoutLength &&
+         info == expiredTimeouts[expiredTimeoutIndex] &&
+         ++expiredTimeoutIndex) ||
+        info->mCanceled) {
+      if (info->mIsInterval && !info->mCanceled) {
+        // Reschedule intervals.
+        info->mTargetTime = info->mTargetTime + info->mInterval;
+        // Don't resort the list here, we'll do that at the end.
+        ++index;
+      }
+      else {
+        mTimeouts.RemoveElement(info);
+      }
+    }
+    else {
+      // If info did not match the current entry in expiredTimeouts, it
+      // shouldn't be there at all.
+      NS_ASSERTION(!expiredTimeouts.Contains(info),
+                   "Our timeouts are out of order!");
+      ++index;
+    }
+  }
+
+  mTimeouts.Sort(comparator);
+
+  // Either signal the parent that we're no longer using timeouts or reschedule
+  // the timer.
+  if (mTimeouts.IsEmpty()) {
+    if (!ModifyBusyCountFromWorker(aCx, false)) {
+      retval = false;
+    }
+    mTimerRunning = false;
+  }
+  else if (retval && !RescheduleTimeoutTimer(aCx)) {
+    retval = false;
+  }
+
+  return retval;
+}
+
+bool
+WorkerPrivate::RescheduleTimeoutTimer(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+  NS_ASSERTION(!mTimeouts.IsEmpty(), "Should have some timeouts!");
+  NS_ASSERTION(mTimer, "Should have a timer!");
+
+  double delta =
+    (mTimeouts[0]->mTargetTime - TimeStamp::Now()).ToMilliseconds();
+  uint32_t delay = delta > 0 ? std::min(delta, double(UINT32_MAX)) : 0;
+
+  nsresult rv = mTimer->InitWithFuncCallback(DummyCallback, nullptr, delay,
+                                             nsITimer::TYPE_ONE_SHOT);
+  if (NS_FAILED(rv)) {
+    JS_ReportError(aCx, "Failed to start timer!");
+    return false;
+  }
+
+  return true;
+}
+
+void
+WorkerPrivate::UpdateRuntimeAndContextOptionsInternal(
+                                    JSContext* aCx,
+                                    const JS::RuntimeOptions& aRuntimeOptions,
+                                    const JS::ContextOptions& aContentCxOptions,
+                                    const JS::ContextOptions& aChromeCxOptions)
+{
+  AssertIsOnWorkerThread();
+
+  JS::RuntimeOptionsRef(aCx) = aRuntimeOptions;
+  JS::ContextOptionsRef(aCx) = IsChromeWorker() ? aChromeCxOptions : aContentCxOptions;
+
+  for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+    mChildWorkers[index]->UpdateRuntimeAndContextOptions(aCx, aRuntimeOptions,
+                                                         aContentCxOptions,
+                                                         aChromeCxOptions);
+  }
+}
+
+void
+WorkerPrivate::UpdatePreferenceInternal(JSContext* aCx, WorkerPreference aPref, bool aValue)
+{
+  AssertIsOnWorkerThread();
+  MOZ_ASSERT(aPref >= 0 && aPref < WORKERPREF_COUNT);
+
+  mPreferences[aPref] = aValue;
+
+  for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+    mChildWorkers[index]->UpdatePreference(aCx, aPref, aValue);
+  }
+}
+
+void
+WorkerPrivate::UpdateJSWorkerMemoryParameterInternal(JSContext* aCx,
+                                                     JSGCParamKey aKey,
+                                                     uint32_t aValue)
+{
+  AssertIsOnWorkerThread();
+
+  // XXX aValue might be 0 here (telling us to unset a previous value for child
+  // workers). Calling JS_SetGCParameter with a value of 0 isn't actually
+  // supported though. We really need some way to revert to a default value
+  // here.
+  if (aValue) {
+    JS_SetGCParameter(JS_GetRuntime(aCx), aKey, aValue);
+  }
+
+  for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+    mChildWorkers[index]->UpdateJSWorkerMemoryParameter(aCx, aKey, aValue);
+  }
+}
+
+#ifdef JS_GC_ZEAL
+void
+WorkerPrivate::UpdateGCZealInternal(JSContext* aCx, uint8_t aGCZeal,
+                                    uint32_t aFrequency)
+{
+  AssertIsOnWorkerThread();
+
+  JS_SetGCZeal(aCx, aGCZeal, aFrequency);
+
+  for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+    mChildWorkers[index]->UpdateGCZeal(aCx, aGCZeal, aFrequency);
+  }
+}
+#endif
+
+void
+WorkerPrivate::GarbageCollectInternal(JSContext* aCx, bool aShrinking,
+                                      bool aCollectChildren)
+{
+  AssertIsOnWorkerThread();
+
+  if (!JS::CurrentGlobalOrNull(aCx)) {
+    // We haven't compiled anything yet. Just bail out.
+    return;
+  }
+
+  if (aShrinking || aCollectChildren) {
+    JSRuntime* rt = JS_GetRuntime(aCx);
+    JS::PrepareForFullGC(rt);
+
+    if (aShrinking) {
+      JS::ShrinkingGC(rt, JS::gcreason::DOM_WORKER);
+
+      if (!aCollectChildren) {
+        LOG(("Worker %p collected idle garbage\n", this));
+      }
+    }
+    else {
+      JS::GCForReason(rt, JS::gcreason::DOM_WORKER);
+      LOG(("Worker %p collected garbage\n", this));
+    }
+  }
+  else {
+    JS_MaybeGC(aCx);
+    LOG(("Worker %p collected periodic garbage\n", this));
+  }
+
+  if (aCollectChildren) {
+    for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+      mChildWorkers[index]->GarbageCollect(aCx, aShrinking);
+    }
+  }
+}
+
+void
+WorkerPrivate::CycleCollectInternal(JSContext* aCx, bool aCollectChildren)
+{
+  AssertIsOnWorkerThread();
+
+  nsCycleCollector_collect(nullptr);
+
+  if (aCollectChildren) {
+    for (uint32_t index = 0; index < mChildWorkers.Length(); index++) {
+      mChildWorkers[index]->CycleCollect(aCx, /* dummy = */ false);
+    }
+  }
+}
+
+void
+WorkerPrivate::SetThread(nsIThread* aThread)
+{
+#ifdef DEBUG
+  if (aThread) {
+    bool isOnCurrentThread;
+    MOZ_ASSERT(NS_SUCCEEDED(aThread->IsOnCurrentThread(&isOnCurrentThread)));
+    MOZ_ASSERT(isOnCurrentThread);
+
+    MOZ_ASSERT(!mPRThread);
+    mPRThread = PRThreadFromThread(aThread);
+    MOZ_ASSERT(mPRThread);
+  }
+  else {
+    MOZ_ASSERT(mPRThread);
+  }
+#endif
+
+  nsCOMPtr<nsIThread> doomedThread;
+
+  { // Scope so that |doomedThread| is released without holding the lock.
+    MutexAutoLock lock(mMutex);
+
+    if (aThread) {
+      MOZ_ASSERT(!mThread);
+      MOZ_ASSERT(mStatus == Pending);
+
+      mThread = aThread;
+
+      if (!mPreStartRunnables.IsEmpty()) {
+        for (uint32_t index = 0; index < mPreStartRunnables.Length(); index++) {
+          MOZ_ALWAYS_TRUE(NS_SUCCEEDED(mThread->Dispatch(
+                                                      mPreStartRunnables[index],
+                                                      NS_DISPATCH_NORMAL)));
+        }
+        mPreStartRunnables.Clear();
+      }
+    }
+    else {
+      MOZ_ASSERT(mThread);
+      mThread.swap(doomedThread);
+    }
+  }
+}
+
+WorkerCrossThreadDispatcher*
+WorkerPrivate::GetCrossThreadDispatcher()
+{
+  MutexAutoLock lock(mMutex);
+
+  if (!mCrossThreadDispatcher && mStatus <= Running) {
+    mCrossThreadDispatcher = new WorkerCrossThreadDispatcher(this);
+  }
+
+  return mCrossThreadDispatcher;
+}
+
+void
+WorkerPrivate::BeginCTypesCall()
+{
+  AssertIsOnWorkerThread();
+
+  // Don't try to GC while we're blocked in a ctypes call.
+  SetGCTimerMode(NoTimer);
+
+  MutexAutoLock lock(mMutex);
+
+  NS_ASSERTION(!mBlockedForMemoryReporter,
+               "Can't be blocked in more than one place at the same time!");
+
+  // Let the main thread know that the worker is effectively blocked while in
+  // this ctypes call. It isn't technically true (obviously the call could do
+  // non-blocking things), but we're assuming that ctypes can't call back into
+  // JSAPI here and therefore any work the ctypes call does will not alter the
+  // data structures of this JS runtime.
+  mBlockedForMemoryReporter = true;
+
+  // The main thread may be waiting on us so it must be notified.
+  mMemoryReportCondVar.Notify();
+}
+
+void
+WorkerPrivate::EndCTypesCall()
+{
+  AssertIsOnWorkerThread();
+
+  {
+    MutexAutoLock lock(mMutex);
+
+    NS_ASSERTION(mBlockedForMemoryReporter, "Somehow we got unblocked!");
+
+    // Don't continue until the memory reporter has finished.
+    while (mMemoryReporterRunning) {
+      mMemoryReportCondVar.Wait();
+    }
+
+    // No need to notify the main thread here as it shouldn't be waiting to see
+    // this state.
+    mBlockedForMemoryReporter = false;
+  }
+
+  // Make sure the periodic timer is running before we start running JS again.
+  SetGCTimerMode(PeriodicTimer);
+}
+
+bool
+WorkerPrivate::ConnectMessagePort(JSContext* aCx, uint64_t aMessagePortSerial)
+{
+  AssertIsOnWorkerThread();
+
+  NS_ASSERTION(!mWorkerPorts.GetWeak(aMessagePortSerial),
+               "Already have this port registered!");
+
+  WorkerGlobalScope* globalScope = GlobalScope();
+
+  JS::Rooted<JSObject*> jsGlobal(aCx, globalScope->GetWrapper());
+  MOZ_ASSERT(jsGlobal);
+
+  nsRefPtr<MessagePort> port = new MessagePort(this, aMessagePortSerial);
+
+  GlobalObject globalObject(aCx, jsGlobal);
+  if (globalObject.Failed()) {
+    return false;
+  }
+
+  RootedDictionary<MessageEventInit> init(aCx);
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mSource.SetValue().SetAsMessagePort() = port;
+
+  ErrorResult rv;
+
+  nsRefPtr<MessageEvent> event =
+    MessageEvent::Constructor(globalObject, aCx,
+                              NS_LITERAL_STRING("connect"), init, rv);
+
+  event->SetTrusted(true);
+
+  nsTArray<nsRefPtr<MessagePortBase>> ports;
+  ports.AppendElement(port);
+
+  nsRefPtr<MessagePortList> portList =
+    new MessagePortList(static_cast<nsIDOMEventTarget*>(globalScope), ports);
+  event->SetPorts(portList);
+
+  mWorkerPorts.Put(aMessagePortSerial, port);
+
+  nsCOMPtr<nsIDOMEvent> domEvent = do_QueryObject(event);
+
+  nsEventStatus dummy = nsEventStatus_eIgnore;
+  globalScope->DispatchDOMEvent(nullptr, domEvent, nullptr, &dummy);
+  return true;
+}
+
+void
+WorkerPrivate::DisconnectMessagePort(uint64_t aMessagePortSerial)
+{
+  AssertIsOnWorkerThread();
+
+  mWorkerPorts.Remove(aMessagePortSerial);
+}
+
+workers::MessagePort*
+WorkerPrivate::GetMessagePort(uint64_t aMessagePortSerial)
+{
+  AssertIsOnWorkerThread();
+
+  nsRefPtr<MessagePort> port;
+  if (mWorkerPorts.Get(aMessagePortSerial, getter_AddRefs(port))) {
+    return port;
+  }
+
+  return nullptr;
+}
+
+JSObject*
+WorkerPrivate::CreateGlobalScope(JSContext* aCx)
+{
+  AssertIsOnWorkerThread();
+
+  nsRefPtr<WorkerGlobalScope> globalScope;
+  if (IsSharedWorker()) {
+    globalScope = new SharedWorkerGlobalScope(this, SharedWorkerName());
+  }
+  else {
+    globalScope = new DedicatedWorkerGlobalScope(this);
+  }
+
+  JS::Rooted<JSObject*> global(aCx, globalScope->WrapGlobalObject(aCx));
+  NS_ENSURE_TRUE(global, nullptr);
+
+  JSAutoCompartment ac(aCx, global);
+
+  if (!RegisterBindings(aCx, global)) {
+    return nullptr;
+  }
+
+  mScope = globalScope.forget();
+
+  JS_FireOnNewGlobalObject(aCx, global);
+
+  return global;
+}
+
+#ifdef DEBUG
+
+void
+WorkerPrivate::AssertIsOnWorkerThread() const
+{
+  // This is much more complicated than it needs to be but we can't use mThread
+  // because it must be protected by mMutex and sometimes this method is called
+  // when mMutex is already locked. This method should always work.
+  MOZ_ASSERT(mPRThread,
+             "AssertIsOnWorkerThread() called before a thread was assigned!");
+
+  MOZ_ASSERT(nsThreadManager::get());
+
+  nsCOMPtr<nsIThread> thread;
+  nsresult rv =
+    nsThreadManager::get()->GetThreadFromPRThread(mPRThread,
+                                                  getter_AddRefs(thread));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_ASSERT(thread);
+
+  bool current;
+  rv = thread->IsOnCurrentThread(&current);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_ASSERT(current, "Wrong thread!");
+}
+
+#endif // DEBUG
+
+NS_IMPL_ISUPPORTS_INHERITED0(ExternalRunnableWrapper, WorkerRunnable)
+
+template <class Derived>
+NS_IMPL_ADDREF(WorkerPrivateParent<Derived>::EventTarget)
+
+template <class Derived>
+NS_IMPL_RELEASE(WorkerPrivateParent<Derived>::EventTarget)
+
+template <class Derived>
+NS_INTERFACE_MAP_BEGIN(WorkerPrivateParent<Derived>::EventTarget)
+  NS_INTERFACE_MAP_ENTRY(nsIEventTarget)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+#ifdef DEBUG
+  // kDEBUGWorkerEventTargetIID is special in that it does not AddRef its
+  // result.
+  if (aIID.Equals(kDEBUGWorkerEventTargetIID)) {
+    *aInstancePtr = this;
+    return NS_OK;
+  }
+  else
+#endif
+NS_INTERFACE_MAP_END
+
+template <class Derived>
+NS_IMETHODIMP
+WorkerPrivateParent<Derived>::
+EventTarget::Dispatch(nsIRunnable* aRunnable, uint32_t aFlags)
+{
+  // May be called on any thread!
+
+  // Workers only support asynchronous dispatch for now.
+  if (NS_WARN_IF(aFlags != NS_DISPATCH_NORMAL)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsRefPtr<WorkerRunnable> workerRunnable;
+
+  MutexAutoLock lock(mMutex);
+
+  if (!mWorkerPrivate) {
+    NS_WARNING("A runnable was posted to a worker that is already shutting "
+               "down!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (aRunnable) {
+    workerRunnable = mWorkerPrivate->MaybeWrapAsWorkerRunnable(aRunnable);
+  }
+
+  nsresult rv =
+    mWorkerPrivate->DispatchPrivate(workerRunnable, mNestedEventTarget);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+template <class Derived>
+NS_IMETHODIMP
+WorkerPrivateParent<Derived>::
+EventTarget::IsOnCurrentThread(bool* aIsOnCurrentThread)
+{
+  // May be called on any thread!
+
+  MOZ_ASSERT(aIsOnCurrentThread);
+
+  MutexAutoLock lock(mMutex);
+
+  if (!mWorkerPrivate) {
+    NS_WARNING("A worker's event target was used after the worker has !");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult rv = mWorkerPrivate->IsOnCurrentThread(aIsOnCurrentThread);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+BEGIN_WORKERS_NAMESPACE
+
+WorkerCrossThreadDispatcher*
+GetWorkerCrossThreadDispatcher(JSContext* aCx, JS::Value aWorker)
+{
+  if (!aWorker.isObject()) {
+    return nullptr;
+  }
+
+  WorkerPrivate* w = nullptr;
+  UNWRAP_OBJECT(Worker, &aWorker.toObject(), w);
+  MOZ_ASSERT(w);
+  return w->GetCrossThreadDispatcher();
+}
+
+JSStructuredCloneCallbacks*
+WorkerStructuredCloneCallbacks(bool aMainRuntime)
+{
+  return aMainRuntime ?
+         &gMainThreadWorkerStructuredCloneCallbacks :
+         &gWorkerStructuredCloneCallbacks;
+}
+
+JSStructuredCloneCallbacks*
+ChromeWorkerStructuredCloneCallbacks(bool aMainRuntime)
+{
+  return aMainRuntime ?
+         &gMainThreadChromeWorkerStructuredCloneCallbacks :
+         &gChromeWorkerStructuredCloneCallbacks;
+}
+
+// Force instantiation.
+template class WorkerPrivateParent<WorkerPrivate>;
+
+END_WORKERS_NAMESPACE