diff -r 000000000000 -r 6474c204b198 dom/events/DataContainerEvent.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/events/DataContainerEvent.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "mozilla/dom/DataContainerEvent.h"
+#include "nsContentUtils.h"
+#include "nsIDocument.h"
+#include "nsIXPConnect.h"
+
+namespace mozilla {
+namespace dom {
+
+DataContainerEvent::DataContainerEvent(EventTarget* aOwner,
+                                       nsPresContext* aPresContext,
+                                       WidgetEvent* aEvent)
+  : Event(aOwner, aPresContext, aEvent)
+{
+  if (mOwner) {
+    if (nsIDocument* doc = mOwner->GetExtantDoc()) {
+      doc->WarnOnceAbout(nsIDocument::eDataContainerEvent);
+    }
+  }
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(DataContainerEvent)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(DataContainerEvent, Event)
+  tmp->mData.Clear();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(DataContainerEvent, Event)
+  tmp->mData.EnumerateRead(TraverseEntry, &cb);
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_ADDREF_INHERITED(DataContainerEvent, Event)
+NS_IMPL_RELEASE_INHERITED(DataContainerEvent, Event)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(DataContainerEvent)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMDataContainerEvent)
+NS_INTERFACE_MAP_END_INHERITING(Event)
+
+NS_IMETHODIMP
+DataContainerEvent::GetData(const nsAString& aKey, nsIVariant** aData)
+{
+  NS_ENSURE_ARG_POINTER(aData);
+
+  mData.Get(aKey, aData);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DataContainerEvent::SetData(const nsAString& aKey, nsIVariant* aData)
+{
+  NS_ENSURE_ARG(aData);
+
+  // Make sure this event isn't already being dispatched.
+  NS_ENSURE_STATE(!mEvent->mFlags.mIsBeingDispatched);
+  mData.Put(aKey, aData);
+  return NS_OK;
+}
+
+void
+DataContainerEvent::SetData(JSContext* aCx, const nsAString& aKey,
+                            JS::Handle<JS::Value> aVal,
+                            ErrorResult& aRv)
+{
+  if (!nsContentUtils::XPConnect()) {
+    aRv = NS_ERROR_FAILURE;
+    return;
+  }
+  nsCOMPtr<nsIVariant> val;
+  nsresult rv =
+    nsContentUtils::XPConnect()->JSToVariant(aCx, aVal, getter_AddRefs(val));
+  if (NS_FAILED(rv)) {
+    aRv = rv;
+    return;
+  }
+  aRv = SetData(aKey, val);
+}
+
+PLDHashOperator
+DataContainerEvent::TraverseEntry(const nsAString& aKey,
+                                  nsIVariant* aDataItem,
+                                  void* aUserArg)
+{
+  nsCycleCollectionTraversalCallback *cb =
+    static_cast<nsCycleCollectionTraversalCallback*>(aUserArg);
+  cb->NoteXPCOMChild(aDataItem);
+
+  return PL_DHASH_NEXT;
+}
+
+} // namespace dom
+} // namespace mozilla
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+nsresult
+NS_NewDOMDataContainerEvent(nsIDOMEvent** aInstancePtrResult,
+                            EventTarget* aOwner,
+                            nsPresContext* aPresContext,
+                            WidgetEvent* aEvent)
+{
+  DataContainerEvent* it = new DataContainerEvent(aOwner, aPresContext, aEvent);
+  NS_ADDREF(it);
+  *aInstancePtrResult = static_cast<Event*>(it);
+  return NS_OK;
+}
+