Hook up Android closed captions 'enabled' setting to Blink

Source/core/html/HTMLMediaElement.cpp

 /*
  * 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 357 matching lines @@
 {
     ASSERT(RuntimeEnabledFeatures::mediaEnabled());
 
     WTF_LOG(Media, "HTMLMediaElement::HTMLMediaElement(%p)", this);
 
     if (document.settings() && document.settings()->mediaPlaybackRequiresUserGesture())
         m_userGestureRequiredForPlay = true;
 
     setHasCustomStyleCallbacks();
     addElementToDocumentMap(this, &document);
+    document.registerForTextTracksVisibilityChangedCallback(this);
+#if OS(ANDROID)

[tkent, 2015/04/29 23:58:44]

Can you set the default value of textTracksEnabled "true", and avoid |#if
OS(ANDROID)|?

[srivats, 2015/05/01 23:03:31]

Doing that will have closed captions turned on by default for videos with tracks
on all platforms and also breaks some media layout tests.

+    // The OS setting for closed captions state is only available on Android, iOS
+    // and OSX. Set closed captions visibility based on OS text tracks state only if the platform
+    // is Android because the setting is currently only plumbed down on Android.
+    setClosedCaptionsVisible(document.settings()->textTracksEnabled());

[tkent, 2015/04/29 23:58:44]

document.settings() can be NULL.

[srivats, 2015/05/01 23:03:31]

Done.

+#endif
 }
 
 HTMLMediaElement::~HTMLMediaElement()
 {
     WTF_LOG(Media, "HTMLMediaElement::~HTMLMediaElement(%p)", this);
 
 #if ENABLE(OILPAN)
     // If the HTMLMediaElement dies with the document we are not
     // allowed to touch the document to adjust delay load event counts
     // because the document could have been already
@@ skipping 18 matching lines @@
         m_textTracks->clearOwner();
     m_audioTracks->shutdown();
     m_videoTracks->shutdown();
 
     if (m_mediaController) {
         m_mediaController->removeMediaElement(this);
         m_mediaController = nullptr;
     }
 #endif
 
+    document().unregisterFromTextTracksVisibilityChangedCallback(this);
+
 #if ENABLE(OILPAN)
     if (m_closeMediaSourceWhenFinalizing)
         closeMediaSource();
 #else
     closeMediaSource();
 
     removeElementFromDocumentMap(this, &document());
 #endif
 
     // Destroying the player may cause a resource load to be canceled,
@@ skipping 2964 matching lines @@
             break;
         }
     }
 
     if (assumption == AssumeNoVisibleChange
         && m_haveVisibleTextTrack == haveVisibleTextTrack) {
         cueTimeline().updateActiveCues(currentTime());
         return;
     }
     m_haveVisibleTextTrack = haveVisibleTextTrack;
+#if !OS(ANDROID)
     m_closedCaptionsVisible = m_haveVisibleTextTrack;
+#else
+    // Set closed captions visible during initial load only if the video has a
+    // visible text track and when the android platform closed captions are enabled.
+    m_closedCaptionsVisible = m_haveVisibleTextTrack && document().settings()->textTracksEnabled();
+#endif
 
     if (!m_haveVisibleTextTrack && !mediaControls())
         return;
 
     if (mediaControls())
         mediaControls()->changedClosedCaptionsVisibility();
 
     cueTimeline().updateActiveCues(currentTime());
 
     // Note: The "time marches on" algorithm (updateActiveCues) runs the "rules
@@ skipping 254 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!visitor->isHeapObjectAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(nullptr);
 }
 #endif
 
 }