Hook up Android closed captions 'enabled' setting to Blink

Source/core/page/Page.cpp

Index: Source/core/page/Page.cpp
diff --git a/Source/core/page/Page.cpp b/Source/core/page/Page.cpp
index 7d325ea83d9445eb6c46849a6e503666e2f62c15..2d3dca81a4064dd655ae7a10f2152f7a2a613086 100644
--- a/Source/core/page/Page.cpp
+++ b/Source/core/page/Page.cpp
@@ -34,6 +34,7 @@
 #include "core/frame/RemoteFrame.h"
 #include "core/frame/RemoteFrameView.h"
 #include "core/frame/Settings.h"
+#include "core/html/HTMLMediaElement.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/TextAutosizer.h"
@@ -495,6 +496,13 @@ void Page::settingsChanged(SettingsDelegate::ChangeType changeType)
             doc->styleResolver()->viewportStyleResolver()->collectViewportRules();
         }
         break;
+    case SettingsDelegate::TextTrackKindUserPreferenceChange:
+        for (Frame* frame = mainFrame(); frame; frame = frame->tree().traverseNext()) {
+            if (frame->isLocalFrame()) {
+                HTMLMediaElement::setTextTrackKindUserPreferenceForAllMediaElements(toLocalFrame(frame)->document());

[philipj_slow, 2015/07/09 15:34:09]

There's a null check for doc above so I guess that document can be null here
too? If so it needs to be handled. Handling it here and passing a reference to
HTMLMediaElement would make it clearly not null at that point, but anything
that's roughly consistent with existing code is fine.

[srivats, 2015/07/09 21:25:37]

Done.

+            }
+        }
+        break;
     }
 }