Merge WebKit r153448 (Optimizes the number of updateTextTrackDisplay calls)

Source/core/html/HTMLMediaElement.h

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 214 matching lines @@
         RefPtr<TextTrack> defaultTrack;
         GroupKind kind;
         bool hasSrcLang;
     };
 
     void configureTextTrackGroupForLanguage(const TrackGroup&) const;
     void configureTextTracks();
     void configureTextTrackGroup(const TrackGroup&);
 
     bool textTracksAreReady() const;
-    void configureTextTrackDisplay();
+    enum VisibilityChangeAssumption {
+        AssumeNoVisibleChange,
+        AssumeVisibleChange
+    };
+    void configureTextTrackDisplay(VisibilityChangeAssumption);
     void updateTextTrackDisplay();
 
     // TextTrackClient
     virtual void textTrackReadyStateChanged(TextTrack*);
     virtual void textTrackKindChanged(TextTrack*);
     virtual void textTrackModeChanged(TextTrack*);
     virtual void textTrackAddCues(TextTrack*, const TextTrackCueList*);
     virtual void textTrackRemoveCues(TextTrack*, const TextTrackCueList*);
     virtual void textTrackAddCue(TextTrack*, PassRefPtr<TextTrackCue>);
     virtual void textTrackRemoveCue(TextTrack*, PassRefPtr<TextTrackCue>);
@@ skipping 362 matching lines @@
 
 inline HTMLMediaElement* toHTMLMediaElement(Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!node || isHTMLMediaElement(node));
     return static_cast<HTMLMediaElement*>(node);
 }
 
 } //namespace
 
 #endif