Improve caption button behavior for video player.

third_party/WebKit/Source/core/html/shadow/MediaControls.h

Index: third_party/WebKit/Source/core/html/shadow/MediaControls.h
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControls.h b/third_party/WebKit/Source/core/html/shadow/MediaControls.h
index 6c1ba2e91a9f6f5fe23fb689b403b37fcfdd0391..02ce2f1b69c8990ffa8b7d7407ebf7f035063485 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControls.h
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControls.h
@@ -34,6 +34,7 @@ namespace blink {
 
 class Event;
 class TextTrackContainer;
+class TextTrackList;
 class MediaControlsWindowEventListener;
 
 class CORE_EXPORT MediaControls final : public HTMLDivElement {
@@ -61,6 +62,8 @@ class CORE_EXPORT MediaControls final : public HTMLDivElement {
   void changedClosedCaptionsVisibility();
   void refreshClosedCaptionsButtonVisibility();
   void toggleTextTrackList();
+  void showTextTrackAtIndex(TextTrackList*, unsigned indexToEnable);
+  void disableShowingTextTracks(TextTrackList*);

[mlamouri (slow - plz ping), 2016/10/28 14:20:15]

Instead of passing TextTrackList, could we get the text track from
m_mediaElement?

[Finnur, 2016/10/29 16:45:18]

Yes, indeed. Much better. PTAL.

 
   void enteredFullscreen();
   void exitedFullscreen();