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 ConfigureTextTrackDisplayFlags {
+        DoNotAssumeVisibleTextTracksChanged,

[acolwell GONE FROM CHROMIUM, 2013/08/12 20:19:02]

nit: Flags doesn't seem appropriate here since the 2 values are mutually
exclusive. How about something like VisibilityChangeAssumption & change the
values to "AssumeNoVisibleChange" & "AssumeVisibleChange"

[vcarbune.chromium, 2013/08/19 22:20:12]

Done. Minimally, this could have been a boolean parameter, but I think this enum
aids readability.

+        AssumeVisibleTextTracksChanged
+    };
+    void configureTextTrackDisplay(ConfigureTextTrackDisplayFlags = DoNotAssumeVisibleTextTracksChanged);

[acolwell GONE FROM CHROMIUM, 2013/08/12 20:19:02]

nit: Do you really need the default argument value here? There appears to be
only two call sites for this method. Any reason not to just explicitly specify
it at the call site that needs it?

[vcarbune.chromium, 2013/08/19 22:20:12]

No, explicitly passed it at each function call.

     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 361 matching lines @@
 
 inline HTMLMediaElement* toMediaElement(Node* node)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!node || isMediaElement(node));
     return static_cast<HTMLMediaElement*>(node);
 }
 
 } //namespace
 
 #endif