diff -r 000000000000 -r 6474c204b198 dom/workers/XMLHttpRequest.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/XMLHttpRequest.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,2313 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* 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 "XMLHttpRequest.h"
+
+#include "nsIDOMEvent.h"
+#include "nsIDOMEventListener.h"
+#include "nsIDOMProgressEvent.h"
+#include "nsIRunnable.h"
+#include "nsIVariant.h"
+#include "nsIXMLHttpRequest.h"
+#include "nsIXPConnect.h"
+
+#include "jsfriendapi.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/dom/Exceptions.h"
+#include "nsComponentManagerUtils.h"
+#include "nsContentUtils.h"
+#include "nsCxPusher.h"
+#include "nsJSUtils.h"
+#include "nsThreadUtils.h"
+
+#include "File.h"
+#include "RuntimeService.h"
+#include "WorkerPrivate.h"
+#include "WorkerRunnable.h"
+#include "XMLHttpRequestUpload.h"
+
+using namespace mozilla;
+
+using namespace mozilla::dom;
+USING_WORKERS_NAMESPACE
+
+// XXX Need to figure this out...
+#define UNCATCHABLE_EXCEPTION NS_ERROR_OUT_OF_MEMORY
+
+/**
+ *  XMLHttpRequest in workers
+ *
+ *  XHR in workers is implemented by proxying calls/events/etc between the
+ *  worker thread and an nsXMLHttpRequest on the main thread.  The glue
+ *  object here is the Proxy, which lives on both threads.  All other objects
+ *  live on either the main thread (the nsXMLHttpRequest) or the worker thread
+ *  (the worker and XHR private objects).
+ *
+ *  The main thread XHR is always operated in async mode, even for sync XHR
+ *  in workers.  Calls made on the worker thread are proxied to the main thread
+ *  synchronously (meaning the worker thread is blocked until the call
+ *  returns).  Each proxied call spins up a sync queue, which captures any
+ *  synchronously dispatched events and ensures that they run synchronously
+ *  on the worker as well.  Asynchronously dispatched events are posted to the
+ *  worker thread to run asynchronously.  Some of the XHR state is mirrored on
+ *  the worker thread to avoid needing a cross-thread call on every property
+ *  access.
+ *
+ *  The XHR private is stored in the private slot of the XHR JSObject on the
+ *  worker thread.  It is destroyed when that JSObject is GCd.  The private
+ *  roots its JSObject while network activity is in progress.  It also
+ *  adds itself as a feature to the worker to give itself a chance to clean up
+ *  if the worker goes away during an XHR call.  It is important that the
+ *  rooting and feature registration (collectively called pinning) happens at
+ *  the proper times.  If we pin for too long we can cause memory leaks or even
+ *  shutdown hangs.  If we don't pin for long enough we introduce a GC hazard.
+ *
+ *  The XHR is pinned from the time Send is called to roughly the time loadend
+ *  is received.  There are some complications involved with Abort and XHR
+ *  reuse.  We maintain a counter on the main thread of how many times Send was
+ *  called on this XHR, and we decrement the counter every time we receive a
+ *  loadend event.  When the counter reaches zero we dispatch a runnable to the
+ *  worker thread to unpin the XHR.  We only decrement the counter if the 
+ *  dispatch was successful, because the worker may no longer be accepting
+ *  regular runnables.  In the event that we reach Proxy::Teardown and there
+ *  the outstanding Send count is still non-zero, we dispatch a control
+ *  runnable which is guaranteed to run.
+ *
+ *  NB: Some of this could probably be simplified now that we have the
+ *  inner/outer channel ids.
+ */
+
+BEGIN_WORKERS_NAMESPACE
+
+class Proxy MOZ_FINAL : public nsIDOMEventListener
+{
+public:
+  // Read on multiple threads.
+  WorkerPrivate* mWorkerPrivate;
+  XMLHttpRequest* mXMLHttpRequestPrivate;
+
+  // XHR Params:
+  bool mMozAnon;
+  bool mMozSystem;
+
+  // Only touched on the main thread.
+  nsRefPtr<nsXMLHttpRequest> mXHR;
+  nsCOMPtr<nsIXMLHttpRequestUpload> mXHRUpload;
+  nsCOMPtr<nsIEventTarget> mSyncLoopTarget;
+  nsCOMPtr<nsIEventTarget> mSyncEventResponseTarget;
+  uint32_t mInnerEventStreamId;
+  uint32_t mInnerChannelId;
+  uint32_t mOutstandingSendCount;
+
+  // Only touched on the worker thread.
+  uint32_t mOuterEventStreamId;
+  uint32_t mOuterChannelId;
+  uint64_t mLastLoaded;
+  uint64_t mLastTotal;
+  uint64_t mLastUploadLoaded;
+  uint64_t mLastUploadTotal;
+  bool mIsSyncXHR;
+  bool mLastLengthComputable;
+  bool mLastUploadLengthComputable;
+  bool mSeenLoadStart;
+  bool mSeenUploadLoadStart;
+
+  // Only touched on the main thread.
+  bool mUploadEventListenersAttached;
+  bool mMainThreadSeenLoadStart;
+  bool mInOpen;
+
+public:
+  Proxy(XMLHttpRequest* aXHRPrivate, bool aMozAnon, bool aMozSystem)
+  : mWorkerPrivate(nullptr), mXMLHttpRequestPrivate(aXHRPrivate),
+    mMozAnon(aMozAnon), mMozSystem(aMozSystem),
+    mInnerEventStreamId(0), mInnerChannelId(0), mOutstandingSendCount(0),
+    mOuterEventStreamId(0), mOuterChannelId(0), mLastLoaded(0), mLastTotal(0),
+    mLastUploadLoaded(0), mLastUploadTotal(0), mIsSyncXHR(false),
+    mLastLengthComputable(false), mLastUploadLengthComputable(false),
+    mSeenLoadStart(false), mSeenUploadLoadStart(false),
+    mUploadEventListenersAttached(false), mMainThreadSeenLoadStart(false),
+    mInOpen(false)
+  { }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIDOMEVENTLISTENER
+
+  bool
+  Init();
+
+  void
+  Teardown();
+
+  bool
+  AddRemoveEventListeners(bool aUpload, bool aAdd);
+
+  void
+  Reset()
+  {
+    AssertIsOnMainThread();
+
+    if (mUploadEventListenersAttached) {
+      AddRemoveEventListeners(true, false);
+    }
+  }
+
+  already_AddRefed<nsIEventTarget>
+  GetEventTarget()
+  {
+    AssertIsOnMainThread();
+
+    nsCOMPtr<nsIEventTarget> target = mSyncEventResponseTarget ?
+                                      mSyncEventResponseTarget :
+                                      mSyncLoopTarget;
+    return target.forget();
+  }
+
+private:
+  ~Proxy()
+  {
+    MOZ_ASSERT(!mXHR);
+    MOZ_ASSERT(!mXHRUpload);
+    MOZ_ASSERT(!mOutstandingSendCount);
+  }
+};
+
+END_WORKERS_NAMESPACE
+
+namespace {
+
+inline void
+ConvertResponseTypeToString(XMLHttpRequestResponseType aType,
+                            nsString& aString)
+{
+  using namespace
+    mozilla::dom::XMLHttpRequestResponseTypeValues;
+
+  size_t index = static_cast<size_t>(aType);
+  MOZ_ASSERT(index < ArrayLength(strings), "Codegen gave us a bad value!");
+
+  aString.AssignASCII(strings[index].value, strings[index].length);
+}
+
+inline XMLHttpRequestResponseType
+ConvertStringToResponseType(const nsAString& aString)
+{
+  using namespace
+    mozilla::dom::XMLHttpRequestResponseTypeValues;
+
+  for (size_t index = 0; index < ArrayLength(strings) - 1; index++) {
+    if (aString.EqualsASCII(strings[index].value, strings[index].length)) {
+      return static_cast<XMLHttpRequestResponseType>(index);
+    }
+  }
+
+  MOZ_ASSUME_UNREACHABLE("Don't know anything about this response type!");
+}
+
+enum
+{
+  STRING_abort = 0,
+  STRING_error,
+  STRING_load,
+  STRING_loadstart,
+  STRING_progress,
+  STRING_timeout,
+  STRING_readystatechange,
+  STRING_loadend,
+
+  STRING_COUNT,
+
+  STRING_LAST_XHR = STRING_loadend,
+  STRING_LAST_EVENTTARGET = STRING_timeout
+};
+
+static_assert(STRING_LAST_XHR >= STRING_LAST_EVENTTARGET, "Bad string setup!");
+static_assert(STRING_LAST_XHR == STRING_COUNT - 1, "Bad string setup!");
+
+const char* const sEventStrings[] = {
+  // nsIXMLHttpRequestEventTarget event types, supported by both XHR and Upload.
+  "abort",
+  "error",
+  "load",
+  "loadstart",
+  "progress",
+  "timeout",
+
+  // nsIXMLHttpRequest event types, supported only by XHR.
+  "readystatechange",
+  "loadend",
+};
+
+static_assert(MOZ_ARRAY_LENGTH(sEventStrings) == STRING_COUNT,
+              "Bad string count!");
+
+class MainThreadProxyRunnable : public MainThreadWorkerSyncRunnable
+{
+protected:
+  nsRefPtr<Proxy> mProxy;
+
+  MainThreadProxyRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy)
+  : MainThreadWorkerSyncRunnable(aWorkerPrivate, aProxy->GetEventTarget()),
+    mProxy(aProxy)
+  {
+    MOZ_ASSERT(aProxy);
+  }
+
+  virtual ~MainThreadProxyRunnable()
+  { }
+};
+
+class XHRUnpinRunnable MOZ_FINAL : public MainThreadWorkerControlRunnable
+{
+  XMLHttpRequest* mXMLHttpRequestPrivate;
+
+public:
+  XHRUnpinRunnable(WorkerPrivate* aWorkerPrivate,
+                   XMLHttpRequest* aXHRPrivate)
+  : MainThreadWorkerControlRunnable(aWorkerPrivate),
+    mXMLHttpRequestPrivate(aXHRPrivate)
+  {
+    MOZ_ASSERT(aXHRPrivate);
+  }
+
+private:
+  ~XHRUnpinRunnable()
+  { }
+
+  bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+  {
+    mXMLHttpRequestPrivate->Unpin();
+
+    return true;
+  }
+};
+
+class AsyncTeardownRunnable MOZ_FINAL : public nsRunnable
+{
+  nsRefPtr<Proxy> mProxy;
+
+public:
+  AsyncTeardownRunnable(Proxy* aProxy)
+  : mProxy(aProxy)
+  {
+    MOZ_ASSERT(aProxy);
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+private:
+  ~AsyncTeardownRunnable()
+  { }
+
+  NS_IMETHOD
+  Run() MOZ_OVERRIDE
+  {
+    AssertIsOnMainThread();
+
+    mProxy->Teardown();
+    mProxy = nullptr;
+
+    return NS_OK;
+  }
+};
+
+class LoadStartDetectionRunnable MOZ_FINAL : public nsRunnable,
+                                             public nsIDOMEventListener
+{
+  WorkerPrivate* mWorkerPrivate;
+  nsRefPtr<Proxy> mProxy;
+  nsRefPtr<nsXMLHttpRequest> mXHR;
+  XMLHttpRequest* mXMLHttpRequestPrivate;
+  nsString mEventType;
+  uint32_t mChannelId;
+  bool mReceivedLoadStart;
+
+  class ProxyCompleteRunnable MOZ_FINAL : public MainThreadProxyRunnable
+  {
+    XMLHttpRequest* mXMLHttpRequestPrivate;
+    uint32_t mChannelId;
+
+  public:
+    ProxyCompleteRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                          XMLHttpRequest* aXHRPrivate, uint32_t aChannelId)
+    : MainThreadProxyRunnable(aWorkerPrivate, aProxy),
+      mXMLHttpRequestPrivate(aXHRPrivate), mChannelId(aChannelId)
+    { }
+
+  private:
+    ~ProxyCompleteRunnable()
+    { }
+
+    virtual bool
+    WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE
+    {
+      if (mChannelId != mProxy->mOuterChannelId) {
+        // Threads raced, this event is now obsolete.
+        return true;
+      }
+
+      if (mSyncLoopTarget) {
+        aWorkerPrivate->StopSyncLoop(mSyncLoopTarget, true);
+      }
+
+      mXMLHttpRequestPrivate->Unpin();
+
+      return true;
+    }
+
+    NS_IMETHOD
+    Cancel() MOZ_OVERRIDE
+    {
+      // This must run!
+      nsresult rv = MainThreadProxyRunnable::Cancel();
+      nsresult rv2 = Run();
+      return NS_FAILED(rv) ? rv : rv2;
+    }
+  };
+
+public:
+  LoadStartDetectionRunnable(Proxy* aProxy, XMLHttpRequest* aXHRPrivate)
+  : mWorkerPrivate(aProxy->mWorkerPrivate), mProxy(aProxy), mXHR(aProxy->mXHR),
+    mXMLHttpRequestPrivate(aXHRPrivate), mChannelId(mProxy->mInnerChannelId),
+    mReceivedLoadStart(false)
+  {
+    AssertIsOnMainThread();
+    mEventType.AssignWithConversion(sEventStrings[STRING_loadstart]);
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIRUNNABLE
+  NS_DECL_NSIDOMEVENTLISTENER
+
+  bool
+  RegisterAndDispatch()
+  {
+    AssertIsOnMainThread();
+
+    if (NS_FAILED(mXHR->AddEventListener(mEventType, this, false, false, 2))) {
+      NS_WARNING("Failed to add event listener!");
+      return false;
+    }
+
+    return NS_SUCCEEDED(NS_DispatchToCurrentThread(this));
+  }
+
+private:
+  ~LoadStartDetectionRunnable()
+  {
+    AssertIsOnMainThread();
+    }
+};
+
+class EventRunnable MOZ_FINAL : public MainThreadProxyRunnable
+{
+  nsString mType;
+  nsString mResponseType;
+  JSAutoStructuredCloneBuffer mResponseBuffer;
+  nsTArray<nsCOMPtr<nsISupports> > mClonedObjects;
+  JS::Heap<JS::Value> mResponse;
+  nsString mResponseText;
+  nsCString mStatusText;
+  uint64_t mLoaded;
+  uint64_t mTotal;
+  uint32_t mEventStreamId;
+  uint32_t mStatus;
+  uint16_t mReadyState;
+  bool mUploadEvent;
+  bool mProgressEvent;
+  bool mLengthComputable;
+  nsresult mResponseTextResult;
+  nsresult mStatusResult;
+  nsresult mResponseResult;
+
+public:
+  class StateDataAutoRooter : private JS::CustomAutoRooter
+  {
+    XMLHttpRequest::StateData* mStateData;
+    MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+
+  public:
+    explicit StateDataAutoRooter(JSContext* aCx, XMLHttpRequest::StateData* aData
+                                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : CustomAutoRooter(aCx), mStateData(aData)
+    {
+      MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+    }
+
+  private:
+    virtual void trace(JSTracer* aTrc)
+    {
+      JS_CallHeapValueTracer(aTrc, &mStateData->mResponse,
+                             "XMLHttpRequest::StateData::mResponse");
+    }
+  };
+
+  EventRunnable(Proxy* aProxy, bool aUploadEvent, const nsString& aType,
+                bool aLengthComputable, uint64_t aLoaded, uint64_t aTotal)
+  : MainThreadProxyRunnable(aProxy->mWorkerPrivate, aProxy), mType(aType),
+    mResponse(JSVAL_VOID), mLoaded(aLoaded), mTotal(aTotal),
+    mEventStreamId(aProxy->mInnerEventStreamId), mStatus(0), mReadyState(0),
+    mUploadEvent(aUploadEvent), mProgressEvent(true),
+    mLengthComputable(aLengthComputable), mResponseTextResult(NS_OK),
+    mStatusResult(NS_OK), mResponseResult(NS_OK)
+  { }
+
+  EventRunnable(Proxy* aProxy, bool aUploadEvent, const nsString& aType)
+  : MainThreadProxyRunnable(aProxy->mWorkerPrivate, aProxy), mType(aType),
+    mResponse(JSVAL_VOID), mLoaded(0), mTotal(0),
+    mEventStreamId(aProxy->mInnerEventStreamId), mStatus(0), mReadyState(0),
+    mUploadEvent(aUploadEvent), mProgressEvent(false), mLengthComputable(0),
+    mResponseTextResult(NS_OK), mStatusResult(NS_OK), mResponseResult(NS_OK)
+  { }
+
+private:
+  ~EventRunnable()
+  { }
+
+  virtual bool
+  PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE;
+
+  virtual bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) MOZ_OVERRIDE;
+};
+
+class WorkerThreadProxySyncRunnable : public nsRunnable
+{
+protected:
+  WorkerPrivate* mWorkerPrivate;
+  nsRefPtr<Proxy> mProxy;
+  nsCOMPtr<nsIEventTarget> mSyncLoopTarget;
+
+private:
+  class ResponseRunnable MOZ_FINAL: public MainThreadStopSyncLoopRunnable
+  {
+    nsRefPtr<Proxy> mProxy;
+    nsresult mErrorCode;
+
+  public:
+    ResponseRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                     nsresult aErrorCode)
+    : MainThreadStopSyncLoopRunnable(aWorkerPrivate, aProxy->GetEventTarget(),
+                                     NS_SUCCEEDED(aErrorCode)),
+      mProxy(aProxy), mErrorCode(aErrorCode)
+    {
+      MOZ_ASSERT(aProxy);
+    }
+
+  private:
+    ~ResponseRunnable()
+    { }
+
+    virtual void
+    MaybeSetException(JSContext* aCx) MOZ_OVERRIDE
+    {
+      MOZ_ASSERT(NS_FAILED(mErrorCode));
+
+      Throw(aCx, mErrorCode);
+    }
+  };
+
+public:
+  WorkerThreadProxySyncRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy)
+  : mWorkerPrivate(aWorkerPrivate), mProxy(aProxy)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+    MOZ_ASSERT(aProxy);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+  }
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  bool
+  Dispatch(JSContext* aCx)
+  {
+    mWorkerPrivate->AssertIsOnWorkerThread();
+
+    AutoSyncLoopHolder syncLoop(mWorkerPrivate);
+    mSyncLoopTarget = syncLoop.EventTarget();
+
+    if (NS_FAILED(NS_DispatchToMainThread(this, NS_DISPATCH_NORMAL))) {
+      JS_ReportError(aCx, "Failed to dispatch to main thread!");
+      return false;
+    }
+
+    return syncLoop.Run();
+  }
+
+protected:
+  virtual ~WorkerThreadProxySyncRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() = 0;
+
+private:
+  NS_DECL_NSIRUNNABLE
+};
+
+class SyncTeardownRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+public:
+  SyncTeardownRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy)
+  { }
+
+private:
+  ~SyncTeardownRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    mProxy->Teardown();
+    MOZ_ASSERT(!mProxy->mSyncLoopTarget);
+    return NS_OK;
+  }
+};
+
+class SetBackgroundRequestRunnable MOZ_FINAL :
+  public WorkerThreadProxySyncRunnable
+{
+  bool mValue;
+
+public:
+  SetBackgroundRequestRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                               bool aValue)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mValue(aValue)
+  { }
+
+private:
+  ~SetBackgroundRequestRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    return mProxy->mXHR->SetMozBackgroundRequest(mValue);
+  }
+};
+
+class SetWithCredentialsRunnable MOZ_FINAL :
+  public WorkerThreadProxySyncRunnable
+{
+  bool mValue;
+
+public:
+  SetWithCredentialsRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                             bool aValue)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mValue(aValue)
+  { }
+
+private:
+  ~SetWithCredentialsRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    return mProxy->mXHR->SetWithCredentials(mValue);
+  }
+};
+
+class SetResponseTypeRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  nsString mResponseType;
+
+public:
+  SetResponseTypeRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                          const nsAString& aResponseType)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy),
+    mResponseType(aResponseType)
+  { }
+
+  void
+  GetResponseType(nsAString& aResponseType)
+  {
+    aResponseType.Assign(mResponseType);
+  }
+
+private:
+  ~SetResponseTypeRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    nsresult rv = mProxy->mXHR->SetResponseType(mResponseType);
+    mResponseType.Truncate();
+    if (NS_SUCCEEDED(rv)) {
+      rv = mProxy->mXHR->GetResponseType(mResponseType);
+    }
+    return rv;
+  }
+};
+
+class SetTimeoutRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  uint32_t mTimeout;
+
+public:
+  SetTimeoutRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                     uint32_t aTimeout)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mTimeout(aTimeout)
+  { }
+
+private:
+  ~SetTimeoutRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    return mProxy->mXHR->SetTimeout(mTimeout);
+  }
+};
+
+class AbortRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+public:
+  AbortRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy)
+  { }
+
+private:
+  ~AbortRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE;
+};
+
+class GetAllResponseHeadersRunnable MOZ_FINAL :
+  public WorkerThreadProxySyncRunnable
+{
+  nsCString& mResponseHeaders;
+
+public:
+  GetAllResponseHeadersRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                                nsCString& aResponseHeaders)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy),
+    mResponseHeaders(aResponseHeaders)
+  { }
+
+private:
+  ~GetAllResponseHeadersRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    mProxy->mXHR->GetAllResponseHeaders(mResponseHeaders);
+    return NS_OK;
+  }
+};
+
+class GetResponseHeaderRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  const nsCString mHeader;
+  nsCString& mValue;
+
+public:
+  GetResponseHeaderRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                            const nsACString& aHeader, nsCString& aValue)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mHeader(aHeader),
+    mValue(aValue)
+  { }
+
+private:
+  ~GetResponseHeaderRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    return mProxy->mXHR->GetResponseHeader(mHeader, mValue);
+  }
+};
+
+class OpenRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  nsCString mMethod;
+  nsString mURL;
+  Optional<nsAString> mUser;
+  nsString mUserStr;
+  Optional<nsAString> mPassword;
+  nsString mPasswordStr;
+  bool mBackgroundRequest;
+  bool mWithCredentials;
+  uint32_t mTimeout;
+
+public:
+  OpenRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+               const nsACString& aMethod, const nsAString& aURL,
+               const Optional<nsAString>& aUser,
+               const Optional<nsAString>& aPassword,
+               bool aBackgroundRequest, bool aWithCredentials,
+               uint32_t aTimeout)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mMethod(aMethod),
+    mURL(aURL), mBackgroundRequest(aBackgroundRequest),
+    mWithCredentials(aWithCredentials), mTimeout(aTimeout)
+  {
+    if (aUser.WasPassed()) {
+      mUserStr = aUser.Value();
+      mUser = &mUserStr;
+    }
+    if (aPassword.WasPassed()) {
+      mPasswordStr = aPassword.Value();
+      mPassword = &mPasswordStr;
+    }
+  }
+
+private:
+  ~OpenRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    WorkerPrivate* oldWorker = mProxy->mWorkerPrivate;
+    mProxy->mWorkerPrivate = mWorkerPrivate;
+
+    nsresult rv = MainThreadRunInternal();
+
+    mProxy->mWorkerPrivate = oldWorker;
+    return rv;
+  }
+
+  nsresult
+  MainThreadRunInternal();
+};
+
+class SendRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  nsString mStringBody;
+  JSAutoStructuredCloneBuffer mBody;
+  nsTArray<nsCOMPtr<nsISupports> > mClonedObjects;
+  nsCOMPtr<nsIEventTarget> mSyncLoopTarget;
+  bool mHasUploadListeners;
+
+public:
+  SendRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+               const nsAString& aStringBody, JSAutoStructuredCloneBuffer&& aBody,
+               nsTArray<nsCOMPtr<nsISupports>>& aClonedObjects,
+               nsIEventTarget* aSyncLoopTarget, bool aHasUploadListeners)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy)
+  , mStringBody(aStringBody)
+  , mBody(Move(aBody))
+  , mSyncLoopTarget(aSyncLoopTarget)
+  , mHasUploadListeners(aHasUploadListeners)
+  {
+    mClonedObjects.SwapElements(aClonedObjects);
+  }
+
+private:
+  ~SendRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE;
+};
+
+class SetRequestHeaderRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  nsCString mHeader;
+  nsCString mValue;
+
+public:
+  SetRequestHeaderRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                           const nsACString& aHeader, const nsACString& aValue)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mHeader(aHeader),
+    mValue(aValue)
+  { }
+
+private:
+  ~SetRequestHeaderRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    return mProxy->mXHR->SetRequestHeader(mHeader, mValue);
+  }
+};
+
+class OverrideMimeTypeRunnable MOZ_FINAL : public WorkerThreadProxySyncRunnable
+{
+  nsString mMimeType;
+
+public:
+  OverrideMimeTypeRunnable(WorkerPrivate* aWorkerPrivate, Proxy* aProxy,
+                           const nsAString& aMimeType)
+  : WorkerThreadProxySyncRunnable(aWorkerPrivate, aProxy), mMimeType(aMimeType)
+  { }
+
+private:
+  ~OverrideMimeTypeRunnable()
+  { }
+
+  virtual nsresult
+  MainThreadRun() MOZ_OVERRIDE
+  {
+    mProxy->mXHR->OverrideMimeType(mMimeType);
+    return NS_OK;
+  }
+};
+
+class AutoUnpinXHR
+{
+  XMLHttpRequest* mXMLHttpRequestPrivate;
+
+public:
+  AutoUnpinXHR(XMLHttpRequest* aXMLHttpRequestPrivate)
+  : mXMLHttpRequestPrivate(aXMLHttpRequestPrivate)
+  {
+    MOZ_ASSERT(aXMLHttpRequestPrivate);
+  }
+
+  ~AutoUnpinXHR()
+  {
+    if (mXMLHttpRequestPrivate) {
+      mXMLHttpRequestPrivate->Unpin();
+    }
+  }
+
+  void Clear()
+  {
+    mXMLHttpRequestPrivate = nullptr;
+  }
+};
+
+} // anonymous namespace
+
+bool
+Proxy::Init()
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(mWorkerPrivate);
+
+  if (mXHR) {
+    return true;
+  }
+
+  nsPIDOMWindow* ownerWindow = mWorkerPrivate->GetWindow();
+  if (ownerWindow) {
+    ownerWindow = ownerWindow->GetOuterWindow();
+    if (!ownerWindow) {
+      NS_ERROR("No outer window?!");
+      return false;
+    }
+
+    nsPIDOMWindow* innerWindow = ownerWindow->GetCurrentInnerWindow();
+    if (mWorkerPrivate->GetWindow() != innerWindow) {
+      NS_WARNING("Window has navigated, cannot create XHR here.");
+      return false;
+    }
+  }
+
+  mXHR = new nsXMLHttpRequest();
+
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(ownerWindow);
+  if (NS_FAILED(mXHR->Init(mWorkerPrivate->GetPrincipal(),
+                           mWorkerPrivate->GetScriptContext(),
+                           global, mWorkerPrivate->GetBaseURI()))) {
+    mXHR = nullptr;
+    return false;
+  }
+
+  mXHR->SetParameters(mMozAnon, mMozSystem);
+
+  if (NS_FAILED(mXHR->GetUpload(getter_AddRefs(mXHRUpload)))) {
+    mXHR = nullptr;
+    return false;
+  }
+
+  if (!AddRemoveEventListeners(false, true)) {
+    mXHRUpload = nullptr;
+    mXHR = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+void
+Proxy::Teardown()
+{
+  AssertIsOnMainThread();
+
+  if (mXHR) {
+    Reset();
+
+    // NB: We are intentionally dropping events coming from xhr.abort on the
+    // floor.
+    AddRemoveEventListeners(false, false);
+    mXHR->Abort();
+
+    if (mOutstandingSendCount) {
+      nsRefPtr<XHRUnpinRunnable> runnable =
+        new XHRUnpinRunnable(mWorkerPrivate, mXMLHttpRequestPrivate);
+      if (!runnable->Dispatch(nullptr)) {
+        NS_RUNTIMEABORT("We're going to hang at shutdown anyways.");
+      }
+
+      if (mSyncLoopTarget) {
+        // We have an unclosed sync loop.  Fix that now.
+        nsRefPtr<MainThreadStopSyncLoopRunnable> runnable =
+          new MainThreadStopSyncLoopRunnable(mWorkerPrivate,
+                                             mSyncLoopTarget.forget(),
+                                             false);
+        if (!runnable->Dispatch(nullptr)) {
+          NS_RUNTIMEABORT("We're going to hang at shutdown anyways.");
+        }
+      }
+
+      mWorkerPrivate = nullptr;
+      mOutstandingSendCount = 0;
+    }
+
+    mXHRUpload = nullptr;
+    mXHR = nullptr;
+  }
+
+  MOZ_ASSERT(!mWorkerPrivate);
+  MOZ_ASSERT(!mSyncLoopTarget);
+}
+
+bool
+Proxy::AddRemoveEventListeners(bool aUpload, bool aAdd)
+{
+  AssertIsOnMainThread();
+
+  NS_ASSERTION(!aUpload ||
+               (mUploadEventListenersAttached && !aAdd) ||
+               (!mUploadEventListenersAttached && aAdd),
+               "Messed up logic for upload listeners!");
+
+  nsCOMPtr<nsIDOMEventTarget> target =
+    aUpload ?
+    do_QueryInterface(mXHRUpload) :
+    do_QueryInterface(static_cast<nsIXMLHttpRequest*>(mXHR.get()));
+  NS_ASSERTION(target, "This should never fail!");
+
+  uint32_t lastEventType = aUpload ? STRING_LAST_EVENTTARGET : STRING_LAST_XHR;
+
+  nsAutoString eventType;
+  for (uint32_t index = 0; index <= lastEventType; index++) {
+    eventType = NS_ConvertASCIItoUTF16(sEventStrings[index]);
+    if (aAdd) {
+      if (NS_FAILED(target->AddEventListener(eventType, this, false))) {
+        return false;
+      }
+    }
+    else if (NS_FAILED(target->RemoveEventListener(eventType, this, false))) {
+      return false;
+    }
+  }
+
+  if (aUpload) {
+    mUploadEventListenersAttached = aAdd;
+  }
+
+  return true;
+}
+
+NS_IMPL_ISUPPORTS(Proxy, nsIDOMEventListener)
+
+NS_IMETHODIMP
+Proxy::HandleEvent(nsIDOMEvent* aEvent)
+{
+  AssertIsOnMainThread();
+
+  if (!mWorkerPrivate || !mXMLHttpRequestPrivate) {
+    NS_ERROR("Shouldn't get here!");
+    return NS_OK;
+  }
+
+  nsString type;
+  if (NS_FAILED(aEvent->GetType(type))) {
+    NS_WARNING("Failed to get event type!");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIDOMEventTarget> target;
+  if (NS_FAILED(aEvent->GetTarget(getter_AddRefs(target)))) {
+    NS_WARNING("Failed to get target!");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIXMLHttpRequestUpload> uploadTarget = do_QueryInterface(target);
+  nsCOMPtr<nsIDOMProgressEvent> progressEvent = do_QueryInterface(aEvent);
+
+  nsRefPtr<EventRunnable> runnable;
+
+  if (mInOpen && type.EqualsASCII(sEventStrings[STRING_readystatechange])) {
+    uint16_t readyState = 0;
+    if (NS_SUCCEEDED(mXHR->GetReadyState(&readyState)) &&
+        readyState == nsIXMLHttpRequest::OPENED) {
+      mInnerEventStreamId++;
+    }
+  }
+
+  if (progressEvent) {
+    bool lengthComputable;
+    uint64_t loaded, total;
+    if (NS_FAILED(progressEvent->GetLengthComputable(&lengthComputable)) ||
+        NS_FAILED(progressEvent->GetLoaded(&loaded)) ||
+        NS_FAILED(progressEvent->GetTotal(&total))) {
+      NS_WARNING("Bad progress event!");
+      return NS_ERROR_FAILURE;
+    }
+    runnable = new EventRunnable(this, !!uploadTarget, type, lengthComputable,
+                                 loaded, total);
+  }
+  else {
+    runnable = new EventRunnable(this, !!uploadTarget, type);
+  }
+
+  {
+    AutoSafeJSContext cx;
+    JSAutoRequest ar(cx);
+    runnable->Dispatch(cx);
+  }
+
+  if (!uploadTarget) {
+    if (type.EqualsASCII(sEventStrings[STRING_loadstart])) {
+      NS_ASSERTION(!mMainThreadSeenLoadStart, "Huh?!");
+      mMainThreadSeenLoadStart = true;
+    }
+    else if (mMainThreadSeenLoadStart &&
+             type.EqualsASCII(sEventStrings[STRING_loadend])) {
+      mMainThreadSeenLoadStart = false;
+
+      nsRefPtr<LoadStartDetectionRunnable> runnable =
+        new LoadStartDetectionRunnable(this, mXMLHttpRequestPrivate);
+      if (!runnable->RegisterAndDispatch()) {
+        NS_WARNING("Failed to dispatch LoadStartDetectionRunnable!");
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED0(WorkerThreadProxySyncRunnable, nsRunnable)
+
+NS_IMPL_ISUPPORTS_INHERITED0(AsyncTeardownRunnable, nsRunnable)
+
+NS_IMPL_ISUPPORTS_INHERITED(LoadStartDetectionRunnable, nsRunnable,
+                                                        nsIDOMEventListener)
+
+NS_IMETHODIMP
+LoadStartDetectionRunnable::Run()
+{
+  AssertIsOnMainThread();
+
+  if (NS_FAILED(mXHR->RemoveEventListener(mEventType, this, false))) {
+    NS_WARNING("Failed to remove event listener!");
+  }
+
+  if (!mReceivedLoadStart) {
+    if (mProxy->mOutstandingSendCount > 1) {
+      mProxy->mOutstandingSendCount--;
+    } else if (mProxy->mOutstandingSendCount == 1) {
+      mProxy->Reset();
+
+      nsRefPtr<ProxyCompleteRunnable> runnable =
+        new ProxyCompleteRunnable(mWorkerPrivate, mProxy,
+                                  mXMLHttpRequestPrivate, mChannelId);
+      if (runnable->Dispatch(nullptr)) {
+        mProxy->mWorkerPrivate = nullptr;
+        mProxy->mSyncLoopTarget = nullptr;
+        mProxy->mOutstandingSendCount--;
+      }
+    }
+  }
+
+  mProxy = nullptr;
+  mXHR = nullptr;
+  mXMLHttpRequestPrivate = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+LoadStartDetectionRunnable::HandleEvent(nsIDOMEvent* aEvent)
+{
+  AssertIsOnMainThread();
+
+#ifdef DEBUG
+  {
+    nsString type;
+    if (NS_SUCCEEDED(aEvent->GetType(type))) {
+      MOZ_ASSERT(type == mEventType);
+    }
+    else {
+      NS_WARNING("Failed to get event type!");
+    }
+  }
+#endif
+
+  mReceivedLoadStart = true;
+  return NS_OK;
+}
+
+bool
+EventRunnable::PreDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+{
+  AssertIsOnMainThread();
+
+  nsRefPtr<nsXMLHttpRequest>& xhr = mProxy->mXHR;
+  MOZ_ASSERT(xhr);
+
+  if (NS_FAILED(xhr->GetResponseType(mResponseType))) {
+    MOZ_ASSERT(false, "This should never fail!");
+  }
+
+  mResponseTextResult = xhr->GetResponseText(mResponseText);
+  if (NS_SUCCEEDED(mResponseTextResult)) {
+    mResponseResult = mResponseTextResult;
+    if (mResponseText.IsVoid()) {
+      mResponse = JSVAL_NULL;
+    }
+  }
+  else {
+    JS::Rooted<JS::Value> response(aCx);
+    mResponseResult = xhr->GetResponse(aCx, &response);
+    if (NS_SUCCEEDED(mResponseResult)) {
+      if (JSVAL_IS_UNIVERSAL(response)) {
+        mResponse = response;
+      }
+      else {
+        // Anything subject to GC must be cloned.
+        JSStructuredCloneCallbacks* callbacks =
+          aWorkerPrivate->IsChromeWorker() ?
+          ChromeWorkerStructuredCloneCallbacks(true) :
+          WorkerStructuredCloneCallbacks(true);
+
+        nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+
+        if (mResponseBuffer.write(aCx, response, callbacks, &clonedObjects)) {
+          mClonedObjects.SwapElements(clonedObjects);
+        }
+        else {
+          NS_WARNING("Failed to clone response!");
+          mResponseResult = NS_ERROR_DOM_DATA_CLONE_ERR;
+        }
+      }
+    }
+  }
+
+  mStatusResult = xhr->GetStatus(&mStatus);
+
+  xhr->GetStatusText(mStatusText);
+
+  mReadyState = xhr->ReadyState();
+
+  return true;
+}
+
+bool
+EventRunnable::WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+{
+  if (mEventStreamId != mProxy->mOuterEventStreamId) {
+    // Threads raced, this event is now obsolete.
+    return true;
+  }
+
+  if (!mProxy->mXMLHttpRequestPrivate) {
+    // Object was finalized, bail.
+    return true;
+  }
+
+  if (mType.EqualsASCII(sEventStrings[STRING_loadstart])) {
+    if (mUploadEvent) {
+      mProxy->mSeenUploadLoadStart = true;
+    }
+    else {
+      mProxy->mSeenLoadStart = true;
+    }
+  }
+  else if (mType.EqualsASCII(sEventStrings[STRING_loadend])) {
+    if (mUploadEvent) {
+      mProxy->mSeenUploadLoadStart = false;
+    }
+    else {
+      mProxy->mSeenLoadStart = false;
+    }
+  }
+  else if (mType.EqualsASCII(sEventStrings[STRING_abort])) {
+    if ((mUploadEvent && !mProxy->mSeenUploadLoadStart) ||
+        (!mUploadEvent && !mProxy->mSeenLoadStart)) {
+      // We've already dispatched premature abort events.
+      return true;
+    }
+  }
+  else if (mType.EqualsASCII(sEventStrings[STRING_readystatechange])) {
+    if (mReadyState == 4 && !mUploadEvent && !mProxy->mSeenLoadStart) {
+      // We've already dispatched premature abort events.
+      return true;
+    }
+  }
+
+  if (mProgressEvent) {
+    // Cache these for premature abort events.
+    if (mUploadEvent) {
+      mProxy->mLastUploadLengthComputable = mLengthComputable;
+      mProxy->mLastUploadLoaded = mLoaded;
+      mProxy->mLastUploadTotal = mTotal;
+    }
+    else {
+      mProxy->mLastLengthComputable = mLengthComputable;
+      mProxy->mLastLoaded = mLoaded;
+      mProxy->mLastTotal = mTotal;
+    }
+  }
+
+  nsAutoPtr<XMLHttpRequest::StateData> state(new XMLHttpRequest::StateData());
+  StateDataAutoRooter rooter(aCx, state);
+
+  state->mResponseTextResult = mResponseTextResult;
+  state->mResponseText = mResponseText;
+
+  if (NS_SUCCEEDED(mResponseTextResult)) {
+    MOZ_ASSERT(JSVAL_IS_VOID(mResponse) || JSVAL_IS_NULL(mResponse));
+    state->mResponseResult = mResponseTextResult;
+    state->mResponse = mResponse;
+  }
+  else {
+    state->mResponseResult = mResponseResult;
+
+    if (NS_SUCCEEDED(mResponseResult)) {
+      if (mResponseBuffer.data()) {
+        MOZ_ASSERT(JSVAL_IS_VOID(mResponse));
+
+        JSAutoStructuredCloneBuffer responseBuffer(Move(mResponseBuffer));
+
+        JSStructuredCloneCallbacks* callbacks =
+          aWorkerPrivate->IsChromeWorker() ?
+          ChromeWorkerStructuredCloneCallbacks(false) :
+          WorkerStructuredCloneCallbacks(false);
+
+        nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+        clonedObjects.SwapElements(mClonedObjects);
+
+        JS::Rooted<JS::Value> response(aCx);
+        if (!responseBuffer.read(aCx, &response, callbacks, &clonedObjects)) {
+          return false;
+        }
+
+        state->mResponse = response;
+      }
+      else {
+        state->mResponse = mResponse;
+      }
+    }
+  }
+
+  state->mStatusResult = mStatusResult;
+  state->mStatus = mStatus;
+
+  state->mStatusText = mStatusText;
+
+  state->mReadyState = mReadyState;
+
+  XMLHttpRequest* xhr = mProxy->mXMLHttpRequestPrivate;
+  xhr->UpdateState(*state);
+
+  if (mUploadEvent && !xhr->GetUploadObjectNoCreate()) {
+    return true;
+  }
+
+  JS::Rooted<JSString*> type(aCx,
+    JS_NewUCStringCopyN(aCx, mType.get(), mType.Length()));
+  if (!type) {
+    return false;
+  }
+
+  nsXHREventTarget* target;
+  if (mUploadEvent) {
+    target = xhr->GetUploadObjectNoCreate();
+  }
+  else {
+    target = xhr;
+  }
+
+  MOZ_ASSERT(target);
+
+  nsCOMPtr<nsIDOMEvent> event;
+  if (mProgressEvent) {
+    NS_NewDOMProgressEvent(getter_AddRefs(event), target, nullptr, nullptr);
+    nsCOMPtr<nsIDOMProgressEvent> progress = do_QueryInterface(event);
+
+    if (progress) {
+      progress->InitProgressEvent(mType, false, false, mLengthComputable,
+                                  mLoaded, mTotal);
+    }
+  }
+  else {
+    NS_NewDOMEvent(getter_AddRefs(event), target, nullptr, nullptr);
+
+    if (event) {
+      event->InitEvent(mType, false, false);
+    }
+  }
+
+  if (!event) {
+    return false;
+  }
+
+  event->SetTrusted(true);
+
+  target->DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+
+  // After firing the event set mResponse to JSVAL_NULL for chunked response
+  // types.
+  if (StringBeginsWith(mResponseType, NS_LITERAL_STRING("moz-chunked-"))) {
+    xhr->NullResponseText();
+  }
+
+  return true;
+}
+
+NS_IMETHODIMP
+WorkerThreadProxySyncRunnable::Run()
+{
+  AssertIsOnMainThread();
+
+  nsCOMPtr<nsIEventTarget> tempTarget;
+  mSyncLoopTarget.swap(tempTarget);
+
+  mProxy->mSyncEventResponseTarget.swap(tempTarget);
+
+  nsresult rv = MainThreadRun();
+
+  nsRefPtr<ResponseRunnable> response =
+    new ResponseRunnable(mWorkerPrivate, mProxy, rv);
+  if (!response->Dispatch(nullptr)) {
+    MOZ_ASSERT(false, "Failed to dispatch response!");
+  }
+
+  mProxy->mSyncEventResponseTarget.swap(tempTarget);
+
+  return NS_OK;
+}
+
+nsresult
+AbortRunnable::MainThreadRun()
+{
+  mProxy->mInnerEventStreamId++;
+
+  WorkerPrivate* oldWorker = mProxy->mWorkerPrivate;
+  mProxy->mWorkerPrivate = mWorkerPrivate;
+
+  mProxy->mXHR->Abort();
+
+  mProxy->mWorkerPrivate = oldWorker;
+
+  mProxy->Reset();
+
+  return NS_OK;
+}
+
+nsresult
+OpenRunnable::MainThreadRunInternal()
+{
+  if (!mProxy->Init()) {
+    return NS_ERROR_DOM_INVALID_STATE_ERR;
+  }
+
+  nsresult rv;
+
+  if (mBackgroundRequest) {
+    rv = mProxy->mXHR->SetMozBackgroundRequest(mBackgroundRequest);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mWithCredentials) {
+    rv = mProxy->mXHR->SetWithCredentials(mWithCredentials);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mTimeout) {
+    rv = mProxy->mXHR->SetTimeout(mTimeout);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  MOZ_ASSERT(!mProxy->mInOpen);
+  mProxy->mInOpen = true;
+
+  ErrorResult rv2;
+  mProxy->mXHR->Open(mMethod, mURL, true, mUser, mPassword, rv2);
+
+  MOZ_ASSERT(mProxy->mInOpen);
+  mProxy->mInOpen = false;
+
+  if (rv2.Failed()) {
+    return rv2.ErrorCode();
+  }
+
+  return mProxy->mXHR->SetResponseType(NS_LITERAL_STRING("text"));
+}
+
+
+nsresult
+SendRunnable::MainThreadRun()
+{
+  nsCOMPtr<nsIVariant> variant;
+
+  if (mBody.data()) {
+    AutoSafeJSContext cx;
+    JSAutoRequest ar(cx);
+
+    nsIXPConnect* xpc = nsContentUtils::XPConnect();
+    MOZ_ASSERT(xpc);
+
+    nsresult rv = NS_OK;
+
+    JSStructuredCloneCallbacks* callbacks =
+      mWorkerPrivate->IsChromeWorker() ?
+      ChromeWorkerStructuredCloneCallbacks(true) :
+      WorkerStructuredCloneCallbacks(true);
+
+    JS::Rooted<JS::Value> body(cx);
+    if (mBody.read(cx, &body, callbacks, &mClonedObjects)) {
+      if (NS_FAILED(xpc->JSValToVariant(cx, body, getter_AddRefs(variant)))) {
+        rv = NS_ERROR_DOM_INVALID_STATE_ERR;
+      }
+    }
+    else {
+      rv = NS_ERROR_DOM_DATA_CLONE_ERR;
+    }
+
+    mBody.clear();
+    mClonedObjects.Clear();
+
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  else {
+    nsCOMPtr<nsIWritableVariant> wvariant =
+      do_CreateInstance(NS_VARIANT_CONTRACTID);
+    NS_ENSURE_TRUE(wvariant, NS_ERROR_UNEXPECTED);
+
+    if (NS_FAILED(wvariant->SetAsAString(mStringBody))) {
+      MOZ_ASSERT(false, "This should never fail!");
+    }
+
+    variant = wvariant;
+  }
+
+  MOZ_ASSERT(!mProxy->mWorkerPrivate);
+  mProxy->mWorkerPrivate = mWorkerPrivate;
+
+  MOZ_ASSERT(!mProxy->mSyncLoopTarget);
+  mProxy->mSyncLoopTarget.swap(mSyncLoopTarget);
+
+  if (mHasUploadListeners) {
+    NS_ASSERTION(!mProxy->mUploadEventListenersAttached, "Huh?!");
+    if (!mProxy->AddRemoveEventListeners(true, true)) {
+      MOZ_ASSERT(false, "This should never fail!");
+    }
+  }
+
+  mProxy->mInnerChannelId++;
+
+  nsresult rv = mProxy->mXHR->Send(variant);
+
+  if (NS_SUCCEEDED(rv)) {
+    mProxy->mOutstandingSendCount++;
+
+    if (!mHasUploadListeners) {
+      NS_ASSERTION(!mProxy->mUploadEventListenersAttached, "Huh?!");
+      if (!mProxy->AddRemoveEventListeners(true, true)) {
+        MOZ_ASSERT(false, "This should never fail!");
+      }
+    }
+  }
+
+  return rv;
+}
+
+XMLHttpRequest::XMLHttpRequest(WorkerPrivate* aWorkerPrivate)
+: mWorkerPrivate(aWorkerPrivate),
+  mResponseType(XMLHttpRequestResponseType::Text), mTimeout(0),
+  mRooted(false), mBackgroundRequest(false), mWithCredentials(false),
+  mCanceled(false), mMozAnon(false), mMozSystem(false)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  SetIsDOMBinding();
+
+  mozilla::HoldJSObjects(this);
+}
+
+XMLHttpRequest::~XMLHttpRequest()
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  ReleaseProxy(XHRIsGoingAway);
+
+  MOZ_ASSERT(!mRooted);
+
+  mozilla::DropJSObjects(this);
+}
+
+NS_IMPL_ADDREF_INHERITED(XMLHttpRequest, nsXHREventTarget)
+NS_IMPL_RELEASE_INHERITED(XMLHttpRequest, nsXHREventTarget)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(XMLHttpRequest)
+NS_INTERFACE_MAP_END_INHERITING(nsXHREventTarget)
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(XMLHttpRequest)
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(XMLHttpRequest,
+                                                  nsXHREventTarget)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mUpload)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(XMLHttpRequest,
+                                                nsXHREventTarget)
+  tmp->ReleaseProxy(XHRIsGoingAway);
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mUpload)
+  tmp->mStateData.mResponse.setUndefined();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(XMLHttpRequest,
+                                               nsXHREventTarget)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JSVAL_MEMBER_CALLBACK(mStateData.mResponse)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+JSObject*
+XMLHttpRequest::WrapObject(JSContext* aCx)
+{
+  return XMLHttpRequestBinding_workers::Wrap(aCx, this);
+}
+
+// static
+already_AddRefed<XMLHttpRequest>
+XMLHttpRequest::Constructor(const GlobalObject& aGlobal,
+                            const MozXMLHttpRequestParameters& aParams,
+                            ErrorResult& aRv)
+{
+  JSContext* cx = aGlobal.GetContext();
+  WorkerPrivate* workerPrivate = GetWorkerPrivateFromContext(cx);
+  MOZ_ASSERT(workerPrivate);
+
+  nsRefPtr<XMLHttpRequest> xhr = new XMLHttpRequest(workerPrivate);
+
+  if (workerPrivate->XHRParamsAllowed()) {
+    if (aParams.mMozSystem)
+      xhr->mMozAnon = true;
+    else
+      xhr->mMozAnon = aParams.mMozAnon;
+    xhr->mMozSystem = aParams.mMozSystem;
+  }
+
+  return xhr.forget();
+}
+
+void
+XMLHttpRequest::ReleaseProxy(ReleaseType aType)
+{
+  // Can't assert that we're on the worker thread here because mWorkerPrivate
+  // may be gone.
+
+  if (mProxy) {
+    if (aType == XHRIsGoingAway) {
+      // We're in a GC finalizer, so we can't do a sync call here (and we don't
+      // need to).
+      nsRefPtr<AsyncTeardownRunnable> runnable =
+        new AsyncTeardownRunnable(mProxy);
+      mProxy = nullptr;
+
+      if (NS_FAILED(NS_DispatchToMainThread(runnable))) {
+        NS_ERROR("Failed to dispatch teardown runnable!");
+      }
+    } else {
+      // This isn't necessary if the worker is going away or the XHR is going
+      // away.
+      if (aType == Default) {
+        // Don't let any more events run.
+        mProxy->mOuterEventStreamId++;
+      }
+
+      // We need to make a sync call here.
+      nsRefPtr<SyncTeardownRunnable> runnable =
+        new SyncTeardownRunnable(mWorkerPrivate, mProxy);
+      mProxy = nullptr;
+
+      if (!runnable->Dispatch(nullptr)) {
+        NS_ERROR("Failed to dispatch teardown runnable!");
+      }
+    }
+  }
+}
+
+void
+XMLHttpRequest::MaybePin(ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mRooted) {
+    return;
+  }
+
+  JSContext* cx = GetCurrentThreadJSContext();
+
+  if (!mWorkerPrivate->AddFeature(cx, this)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  NS_ADDREF_THIS();
+
+  mRooted = true;
+}
+
+void
+XMLHttpRequest::MaybeDispatchPrematureAbortEvents(ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+  MOZ_ASSERT(mProxy);
+
+  mStateData.mReadyState = 4;
+
+  if (mProxy->mSeenUploadLoadStart) {
+    MOZ_ASSERT(mUpload);
+
+    DispatchPrematureAbortEvent(mUpload, NS_LITERAL_STRING("abort"), true,
+                                aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    DispatchPrematureAbortEvent(mUpload, NS_LITERAL_STRING("loadend"), true,
+                                aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    mProxy->mSeenUploadLoadStart = false;
+  }
+
+  if (mProxy->mSeenLoadStart) {
+    DispatchPrematureAbortEvent(this, NS_LITERAL_STRING("readystatechange"),
+                                false, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    DispatchPrematureAbortEvent(this, NS_LITERAL_STRING("abort"), false, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    DispatchPrematureAbortEvent(this, NS_LITERAL_STRING("loadend"), false,
+                                aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+
+    mProxy->mSeenLoadStart = false;
+  }
+}
+
+void
+XMLHttpRequest::DispatchPrematureAbortEvent(EventTarget* aTarget,
+                                            const nsAString& aEventType,
+                                            bool aUploadTarget,
+                                            ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+  MOZ_ASSERT(aTarget);
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  nsCOMPtr<nsIDOMEvent> event;
+  if (aEventType.EqualsLiteral("readystatechange")) {
+    NS_NewDOMEvent(getter_AddRefs(event), aTarget, nullptr, nullptr);
+
+    if (event) {
+      event->InitEvent(aEventType, false, false);
+    }
+  }
+  else {
+    NS_NewDOMProgressEvent(getter_AddRefs(event), aTarget, nullptr, nullptr);
+
+    nsCOMPtr<nsIDOMProgressEvent> progress = do_QueryInterface(event);
+    if (progress) {
+      if (aUploadTarget) {
+        progress->InitProgressEvent(aEventType, false, false,
+                                    mProxy->mLastUploadLengthComputable,
+                                    mProxy->mLastUploadLoaded,
+                                    mProxy->mLastUploadTotal);
+      }
+      else {
+        progress->InitProgressEvent(aEventType, false, false,
+                                    mProxy->mLastLengthComputable,
+                                    mProxy->mLastLoaded,
+                                    mProxy->mLastTotal);
+      }
+    }
+  }
+
+  if (!event) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  event->SetTrusted(true);
+
+  aTarget->DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+}
+
+void
+XMLHttpRequest::Unpin()
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  MOZ_ASSERT(mRooted, "Mismatched calls to Unpin!");
+
+  JSContext* cx = GetCurrentThreadJSContext();
+
+  mWorkerPrivate->RemoveFeature(cx, this);
+
+  mRooted = false;
+
+  NS_RELEASE_THIS();
+}
+
+void
+XMLHttpRequest::SendInternal(const nsAString& aStringBody,
+                             JSAutoStructuredCloneBuffer&& aBody,
+                             nsTArray<nsCOMPtr<nsISupports> >& aClonedObjects,
+                             ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  bool hasUploadListeners = mUpload ? mUpload->HasListeners() : false;
+
+  MaybePin(aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  AutoUnpinXHR autoUnpin(this);
+  Maybe<AutoSyncLoopHolder> autoSyncLoop;
+
+  nsCOMPtr<nsIEventTarget> syncLoopTarget;
+  bool isSyncXHR = mProxy->mIsSyncXHR;
+  if (isSyncXHR) {
+    autoSyncLoop.construct(mWorkerPrivate);
+    syncLoopTarget = autoSyncLoop.ref().EventTarget();
+  }
+
+  mProxy->mOuterChannelId++;
+
+  JSContext* cx = mWorkerPrivate->GetJSContext();
+
+  nsRefPtr<SendRunnable> runnable =
+    new SendRunnable(mWorkerPrivate, mProxy, aStringBody, Move(aBody),
+                     aClonedObjects, syncLoopTarget, hasUploadListeners);
+  if (!runnable->Dispatch(cx)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  if (!isSyncXHR)  {
+    autoUnpin.Clear();
+    MOZ_ASSERT(autoSyncLoop.empty());
+    return;
+  }
+
+  autoUnpin.Clear();
+
+  if (!autoSyncLoop.ref().Run()) {
+    aRv.Throw(NS_ERROR_FAILURE);
+  }
+}
+
+bool
+XMLHttpRequest::Notify(JSContext* aCx, Status aStatus)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+  MOZ_ASSERT(mWorkerPrivate->GetJSContext() == aCx);
+
+  if (aStatus >= Canceling && !mCanceled) {
+    mCanceled = true;
+    ReleaseProxy(WorkerIsGoingAway);
+  }
+
+  return true;
+}
+
+void
+XMLHttpRequest::Open(const nsACString& aMethod, const nsAString& aUrl,
+                     bool aAsync, const Optional<nsAString>& aUser,
+                     const Optional<nsAString>& aPassword, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (mProxy) {
+    MaybeDispatchPrematureAbortEvents(aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+  }
+  else {
+    mProxy = new Proxy(this, mMozAnon, mMozSystem);
+  }
+
+  mProxy->mOuterEventStreamId++;
+
+  nsRefPtr<OpenRunnable> runnable =
+    new OpenRunnable(mWorkerPrivate, mProxy, aMethod, aUrl, aUser, aPassword,
+                     mBackgroundRequest, mWithCredentials,
+                     mTimeout);
+
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    ReleaseProxy();
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  mProxy->mIsSyncXHR = !aAsync;
+}
+
+void
+XMLHttpRequest::SetRequestHeader(const nsACString& aHeader,
+                                 const nsACString& aValue, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  nsRefPtr<SetRequestHeaderRunnable> runnable =
+    new SetRequestHeaderRunnable(mWorkerPrivate, mProxy, aHeader, aValue);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+XMLHttpRequest::SetTimeout(uint32_t aTimeout, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  mTimeout = aTimeout;
+
+  if (!mProxy) {
+    // Open may not have been called yet, in which case we'll handle the
+    // timeout in OpenRunnable.
+    return;
+  }
+
+  nsRefPtr<SetTimeoutRunnable> runnable =
+    new SetTimeoutRunnable(mWorkerPrivate, mProxy, aTimeout);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+XMLHttpRequest::SetWithCredentials(bool aWithCredentials, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  mWithCredentials = aWithCredentials;
+
+  if (!mProxy) {
+    // Open may not have been called yet, in which case we'll handle the
+    // credentials in OpenRunnable.
+    return;
+  }
+
+  nsRefPtr<SetWithCredentialsRunnable> runnable =
+    new SetWithCredentialsRunnable(mWorkerPrivate, mProxy, aWithCredentials);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+XMLHttpRequest::SetMozBackgroundRequest(bool aBackgroundRequest,
+                                        ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  mBackgroundRequest = aBackgroundRequest;
+
+  if (!mProxy) {
+    // Open may not have been called yet, in which case we'll handle the
+    // background request in OpenRunnable.
+    return;
+  }
+
+  nsRefPtr<SetBackgroundRequestRunnable> runnable =
+    new SetBackgroundRequestRunnable(mWorkerPrivate, mProxy,
+                                     aBackgroundRequest);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+XMLHttpRequestUpload*
+XMLHttpRequest::GetUpload(ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return nullptr;
+  }
+
+  if (!mUpload) {
+    mUpload = XMLHttpRequestUpload::Create(this);
+
+    if (!mUpload) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+  }
+
+  return mUpload;
+}
+
+void
+XMLHttpRequest::Send(ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  // Nothing to clone.
+  JSAutoStructuredCloneBuffer buffer;
+  nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+
+  SendInternal(NullString(), Move(buffer), clonedObjects, aRv);
+}
+
+void
+XMLHttpRequest::Send(const nsAString& aBody, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  // Nothing to clone.
+  JSAutoStructuredCloneBuffer buffer;
+  nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+
+  SendInternal(aBody, Move(buffer), clonedObjects, aRv);
+}
+
+void
+XMLHttpRequest::Send(JS::Handle<JSObject*> aBody, ErrorResult& aRv)
+{
+  JSContext* cx = mWorkerPrivate->GetJSContext();
+
+  MOZ_ASSERT(aBody);
+
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  JS::Rooted<JS::Value> valToClone(cx);
+  if (JS_IsArrayBufferObject(aBody) || JS_IsArrayBufferViewObject(aBody) ||
+      file::GetDOMBlobFromJSObject(aBody)) {
+    valToClone.setObject(*aBody);
+  }
+  else {
+    JS::Rooted<JS::Value> obj(cx, JS::ObjectValue(*aBody));
+    JSString* bodyStr = JS::ToString(cx, obj);
+    if (!bodyStr) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+    valToClone.setString(bodyStr);
+  }
+
+  JSStructuredCloneCallbacks* callbacks =
+    mWorkerPrivate->IsChromeWorker() ?
+    ChromeWorkerStructuredCloneCallbacks(false) :
+    WorkerStructuredCloneCallbacks(false);
+
+  nsTArray<nsCOMPtr<nsISupports> > clonedObjects;
+
+  JSAutoStructuredCloneBuffer buffer;
+  if (!buffer.write(cx, valToClone, callbacks, &clonedObjects)) {
+    aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
+    return;
+  }
+
+  SendInternal(EmptyString(), Move(buffer), clonedObjects, aRv);
+}
+
+void
+XMLHttpRequest::Send(const ArrayBuffer& aBody, ErrorResult& aRv)
+{
+  JS::Rooted<JSObject*> obj(mWorkerPrivate->GetJSContext(), aBody.Obj());
+  return Send(obj, aRv);
+}
+
+void
+XMLHttpRequest::Send(const ArrayBufferView& aBody, ErrorResult& aRv)
+{
+  JS::Rooted<JSObject*> obj(mWorkerPrivate->GetJSContext(), aBody.Obj());
+  return Send(obj, aRv);
+}
+
+void
+XMLHttpRequest::SendAsBinary(const nsAString& aBody, ErrorResult& aRv)
+{
+  NS_NOTYETIMPLEMENTED("Implement me!");
+  aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
+  return;
+}
+
+void
+XMLHttpRequest::Abort(ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+  }
+
+  if (!mProxy) {
+    return;
+  }
+
+  MaybeDispatchPrematureAbortEvents(aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  mProxy->mOuterEventStreamId++;
+
+  nsRefPtr<AbortRunnable> runnable = new AbortRunnable(mWorkerPrivate, mProxy);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+XMLHttpRequest::GetResponseHeader(const nsACString& aHeader,
+                                  nsACString& aResponseHeader, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  nsCString responseHeader;
+  nsRefPtr<GetResponseHeaderRunnable> runnable =
+    new GetResponseHeaderRunnable(mWorkerPrivate, mProxy, aHeader,
+                                  responseHeader);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+  aResponseHeader = responseHeader;
+}
+
+void
+XMLHttpRequest::GetAllResponseHeaders(nsACString& aResponseHeaders,
+                                      ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  nsCString responseHeaders;
+  nsRefPtr<GetAllResponseHeadersRunnable> runnable =
+    new GetAllResponseHeadersRunnable(mWorkerPrivate, mProxy, responseHeaders);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  aResponseHeaders = responseHeaders;
+}
+
+void
+XMLHttpRequest::OverrideMimeType(const nsAString& aMimeType, ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  // We're supposed to throw if the state is not OPENED or HEADERS_RECEIVED. We
+  // can detect OPENED really easily but we can't detect HEADERS_RECEIVED in a
+  // non-racy way until the XHR state machine actually runs on this thread
+  // (bug 671047). For now we're going to let this work only if the Send()
+  // method has not been called.
+  if (!mProxy || SendInProgress()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  nsRefPtr<OverrideMimeTypeRunnable> runnable =
+    new OverrideMimeTypeRunnable(mWorkerPrivate, mProxy, aMimeType);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+}
+
+void
+XMLHttpRequest::SetResponseType(XMLHttpRequestResponseType aResponseType,
+                                ErrorResult& aRv)
+{
+  mWorkerPrivate->AssertIsOnWorkerThread();
+
+  if (mCanceled) {
+    aRv.Throw(UNCATCHABLE_EXCEPTION);
+    return;
+  }
+
+  if (!mProxy || SendInProgress()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
+  // "document" is fine for the main thread but not for a worker. Short-circuit
+  // that here.
+  if (aResponseType == XMLHttpRequestResponseType::Document) {
+    return;
+  }
+
+  nsString responseType;
+  ConvertResponseTypeToString(aResponseType, responseType);
+
+  nsRefPtr<SetResponseTypeRunnable> runnable =
+    new SetResponseTypeRunnable(mWorkerPrivate, mProxy, responseType);
+  if (!runnable->Dispatch(mWorkerPrivate->GetJSContext())) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return;
+  }
+
+  nsString acceptedResponseTypeString;
+  runnable->GetResponseType(acceptedResponseTypeString);
+
+  mResponseType = ConvertStringToResponseType(acceptedResponseTypeString);
+}
+
+void
+XMLHttpRequest::GetResponse(JSContext* /* unused */,
+                            JS::MutableHandle<JS::Value> aResponse,
+                            ErrorResult& aRv)
+{
+  if (NS_SUCCEEDED(mStateData.mResponseTextResult) &&
+      JSVAL_IS_VOID(mStateData.mResponse)) {
+    MOZ_ASSERT(mStateData.mResponseText.Length());
+    MOZ_ASSERT(NS_SUCCEEDED(mStateData.mResponseResult));
+
+    JSString* str =
+      JS_NewUCStringCopyN(mWorkerPrivate->GetJSContext(),
+                          mStateData.mResponseText.get(),
+                          mStateData.mResponseText.Length());
+    if (!str) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+
+    mStateData.mResponse = STRING_TO_JSVAL(str);
+  }
+
+  JS::ExposeValueToActiveJS(mStateData.mResponse);
+  aRv = mStateData.mResponseResult;
+  aResponse.set(mStateData.mResponse);
+}
+
+void
+XMLHttpRequest::GetResponseText(nsAString& aResponseText, ErrorResult& aRv)
+{
+  aRv = mStateData.mResponseTextResult;
+  aResponseText = mStateData.mResponseText;
+}
+
+void
+XMLHttpRequest::UpdateState(const StateData& aStateData)
+{
+  mStateData = aStateData;
+}