Support text track selection in video controls

content/app/strings/content_strings.grd

Index: content/app/strings/content_strings.grd
diff --git a/content/app/strings/content_strings.grd b/content/app/strings/content_strings.grd
index 452730f5e578653dd2ae90932af5e0ee4675d572..e24e7b2fe6c16b9f7958c777ed051c7b768c893a 100644
--- a/content/app/strings/content_strings.grd
+++ b/content/app/strings/content_strings.grd
@@ -606,11 +606,11 @@ below:
       <message name="IDS_AX_MEDIA_HIDE_CLOSED_CAPTIONS_BUTTON" desc="accessibility role description for hide closed captions button">
         hide closed captions
       </message>
-      
+
       <message name="IDS_AX_MEDIA_CAST_OFF_BUTTON" desc="accessibility role description for remote playback button">
         play on remote device
       </message>
-      
+
       <message name="IDS_AX_MEDIA_CAST_ON_BUTTON" desc="accessibility role description for remote playback control button">
         control remote playback
       </message>
@@ -682,7 +682,7 @@ below:
       <message name="IDS_AX_MEDIA_CAST_OFF_BUTTON_HELP" desc="accessibility help description for remote playback button">
         play on remote device
       </message>
-      
+
       <message name="IDS_AX_MEDIA_CAST_ON_BUTTON_HELP" desc="accessibility help description for remote playback control button">
         control remote playback
       </message>
@@ -847,8 +847,16 @@ below:
         Please lengthen this text to <ph name="MIN_CHARACTERS">$2<ex>101</ex></ph> characters or more (you are currently using <ph name="CURRENT_LENGTH">$1<ex>100</ex></ph> characters).
       </message>
 
-      <message name="IDS_PLUGIN_INITIALIZATION_ERROR" desc="A message displayed when a plugin failed to load">
-        Couldn't load plugin.
+      <message name="IDS_MEDIA_TRACKS_NO_LABEL" desc="Menu item label for a text track that has no name specified">
+        Unknown
+      </message>
+
+      <message name="IDS_MEDIA_TRACKS_OFF" desc="Menu item label for a text track that represents disabling closed captions">
+        Off
+      </message>
+
+      <message name="IDS_PLUGIN_INITIALIZATION_ERROR" desc="A message displayed when a plug-in failed to load">

[philipj_slow, 2016/03/01 08:51:40]

It looks like you have accidentally reverted part of
https://codereview.chromium.org/1007443004 here, presumably when resolving a
conflict.

[srivats, 2016/03/30 00:46:42]

Sorry. Fixed it

+        Couldn't load plug-in.
       </message>
 
     </messages>