Bug 1279865 - Don't run TimeMarchesOn if the MediaElement is not played. r=rillian

1. If mHasUserInteraction MediaElement is false, don't run the TimeMarchesOn because the element is not played. 2. Update the activeCueList only in TimeMarchesOn(). 3. Run TimeMarchesOn() at the beginning of play. r=rillian

MozReview-Commit-ID: BhwsIfRm3B2

dom/html/HTMLMediaElement.h

@@ -713,6 +713,14 @@ public:
     }
   }
 
+  bool GetHasUserInteraction()
+  {
+    return mHasUserInteraction;
+  }
+
+  // A method to check whether we are currently playing.
+  bool IsCurrentlyPlaying() const;
+
   /**
    * A public wrapper for FinishDecoderSetup()
    */
@@ -1138,9 +1146,6 @@ protected:
   // A method to check if we are playing through the AudioChannel.
   bool IsPlayingThroughTheAudioChannel() const;
 
-  // A method to check whether we are currently playing.
-  bool IsCurrentlyPlaying() const;
-
   // Update the audio channel playing state
   void UpdateAudioChannelPlayingState();