Media Controls: Use events to update controls for closed captions.

third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp

Index: third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
diff --git a/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp b/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
index 154591d58a1b3a10bdccae55c949efae85858152..c9da64a9860dea386cd8e284c72a5e5b96d7d9d4 100644
--- a/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
+++ b/third_party/WebKit/Source/core/html/shadow/MediaControlsMediaEventListener.cpp
@@ -7,6 +7,7 @@
 #include "core/events/Event.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/shadow/MediaControls.h"
+#include "core/html/track/TextTrackList.h"
 
 namespace blink {
 
@@ -23,6 +24,12 @@ MediaControlsMediaEventListener::MediaControlsMediaEventListener(
                                                     false);
   m_mediaControls->m_mediaElement->addEventListener(EventTypeNames::pause, this,
                                                     false);
+
+  // TextTracks events.
+  TextTrackList* textTracks = m_mediaControls->m_mediaElement->textTracks();
+  textTracks->addEventListener(EventTypeNames::addtrack, this, false);
+  textTracks->addEventListener(EventTypeNames::change, this, false);
+  textTracks->addEventListener(EventTypeNames::removetrack, this, false);
 }
 
 bool MediaControlsMediaEventListener::operator==(
@@ -54,6 +61,17 @@ void MediaControlsMediaEventListener::handleEvent(
     return;
   }
 
+  // TextTracks events.
+  if (event->type() == EventTypeNames::addtrack ||
+      event->type() == EventTypeNames::removetrack) {
+    m_mediaControls->onTextTracksAddedRemoved();
+    return;
+  }
+  if (event->type() == EventTypeNames::change) {
+    m_mediaControls->onTextTracksChanged();
+    return;
+  }
+
   NOTREACHED();
 }