Bug 464398 - Stop HTML media elements from firing events in bfcache - r=roc a=blocking2.0

content/html/content/public/nsHTMLMediaElement.h

@@ -191,6 +191,9 @@ public:
                                        PRUint32 aFrameBufferLength,
                                        PRUint64 aTime);
 
+  // Dispatch events that were raised while in the bfcache
+  nsresult DispatchPendingMediaEvents();
+
   // Called by the decoder when some data has been downloaded or
   // buffering/seeking has ended. aNextFrameAvailable is true when
   // the data for the next frame is available. This method will
@@ -532,6 +535,10 @@ protected:
   // we're bound to when loading starts.
   nsCOMPtr<nsIDocument> mLoadBlockedDoc;
 
+  // Contains names of events that have been raised while in the bfcache.
+  // These events get re-dispatched when the bfcache is exited.
+  nsTArray<nsString> mPendingEvents;
+
   // Media loading flags. See:
   //   http://www.whatwg.org/specs/web-apps/current-work/#video)
   nsMediaNetworkState mNetworkState;

content/html/content/src/nsHTMLMediaElement.cpp

@@ -59,8 +59,8 @@
 #include "nsThreadUtils.h"
 #include "nsIThreadInternal.h"
 #include "nsContentUtils.h"
-#include "nsFrameManager.h"
 
+#include "nsFrameManager.h"
 #include "nsIScriptSecurityManager.h"
 #include "nsIXPConnect.h"
 #include "jsapi.h"
@@ -2245,6 +2245,13 @@ nsresult nsHTMLMediaElement::DispatchEvent(const nsAString& aName)
   LOG_EVENT(PR_LOG_DEBUG, ("%p Dispatching event %s", this,
                           NS_ConvertUTF16toUTF8(aName).get()));
 
+  // Save events that occur while in the bfcache. These will be dispatched
+  // if the page comes out of the bfcache.
+  if (mPausedForInactiveDocument) {
+    mPendingEvents.AppendElement(aName);
+    return NS_OK;
+  }
+
   return nsContentUtils::DispatchTrustedEvent(GetOwnerDoc(),
                                               static_cast<nsIContent*>(this),
                                               aName,
@@ -2262,6 +2269,20 @@ nsresult nsHTMLMediaElement::DispatchAsyncEvent(const nsAString& aName)
   return NS_OK;
 }
 
+nsresult nsHTMLMediaElement::DispatchPendingMediaEvents()
+{
+  NS_ASSERTION(!mPausedForInactiveDocument,
+               "Must not be in bfcache when dispatching pending media events");
+
+  PRUint32 count = mPendingEvents.Length();
+  for (PRUint32 i = 0; i < count; ++i) {
+    DispatchAsyncEvent(mPendingEvents[i]);
+  }
+  mPendingEvents.Clear();
+
+  return NS_OK;
+}
+
 PRBool nsHTMLMediaElement::IsPotentiallyPlaying() const
 {
   // TODO:
@@ -2312,6 +2333,7 @@ void nsHTMLMediaElement::NotifyOwnerDocumentActivityChanged()
         mDecoder->Suspend();
       } else {
         mDecoder->Resume(PR_FALSE);
+        DispatchPendingMediaEvents();
         if (!mPaused && !mDecoder->IsEnded()) {
           mDecoder->Play();
         }