Bug 1390443. P1 - don't change nextFrameStatus when MDSM reaches the end of playback. r=cpearce

Instead, MediaDecoder::NextFrameStatus() checks IsEnded() and returns
NEXT_FRAME_UNAVAILABLE to ensure we have HAVE_CURRENT_DATA when playback
is ended on the main thread.

This will fix the timing issue (comment 0) which causes 'waiting' to fire.

MozReview-Commit-ID: 7O21x2q0lb8

--HG--
extra : rebase_source : bbd898edfb5f4a47a5062dd2bc916c911caf0c8e
extra : intermediate-source : 2b3e413db02a7aad00d13fdf274b346bccafc414
extra : source : 6f60fad11b65e75b456e128f8414fe2ea545455f

dom/html/HTMLMediaElement.cpp

@@ -5824,14 +5824,6 @@ HTMLMediaElement::UpdateReadyStateInternal()
     return;
   }
 
-  if (mDecoder && !mDecoder->IsEnded() &&
-      !mDecoder->GetResource()->IsExpectingMoreData()) {
-    LOG(LogLevel::Debug, ("MediaElement %p UpdateReadyStateInternal() "
-                          "Decoder fetched all data for media resource", this));
-    ChangeReadyState(nsIDOMHTMLMediaElement::HAVE_ENOUGH_DATA);
-    return;
-  }
-
   if (nextFrameStatus != MediaDecoderOwner::NEXT_FRAME_AVAILABLE) {
     LOG(LogLevel::Debug, ("MediaElement %p UpdateReadyStateInternal() "
                           "Next frame not available", this));

dom/media/MediaDecoder.h

@@ -400,8 +400,9 @@ private:
 
   virtual MediaDecoderOwner::NextFrameStatus NextFrameStatus()
   {
-    return mNextFrameStatus;
+    return !IsEnded() ? mNextFrameStatus : MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE;
   }
+
   virtual MediaDecoderOwner::NextFrameStatus NextFrameBufferedStatus();
 
   // Returns a string describing the state of the media player internal

dom/media/MediaDecoderStateMachine.cpp

@@ -2006,9 +2006,6 @@ public:
       }
       mMaster->UpdatePlaybackPosition(clockTime);
 
-      // Ensure readyState is updated before firing the 'ended' event.
-      mMaster->UpdateNextFrameStatus(MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE);
-
       mMaster->mOnPlaybackEvent.Notify(MediaEventType::PlaybackEnded);
 
       mSentPlaybackEndedEvent = true;