Implement <video controls> dodging for text track layout

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 3208 matching lines @@
 
     assertShadowRootChildren(shadowRoot);
 
     return *textTrackContainer;
 }
 
 void HTMLMediaElement::updateTextTrackDisplay()
 {
     WTF_LOG(Media, "HTMLMediaElement::updateTextTrackDisplay(%p)", this);
 
-    ensureTextTrackContainer().updateDisplay(*this);
+    ensureTextTrackContainer().updateDisplay(*this, TextTrackContainer::DidNotStartExposingControls);
+}
+
+void HTMLMediaElement::mediaControlsDidBecomeVisible()
+{
+    WTF_LOG(Media, "HTMLMediaElement::mediaControlsDidBecomeVisible(%p)", this);
+
+    // When the user agent starts exposing a user interface for a video element,
+    // the user agent should run the rules for updating the text track rendering
+    // of each of the text tracks in the video element's list of text tracks ...
+    if (isHTMLVideoElement() && closedCaptionsVisible())
+        ensureTextTrackContainer().updateDisplay(*this, TextTrackContainer::DidStartExposingControls);
 }
 
 void HTMLMediaElement::setClosedCaptionsVisible(bool closedCaptionVisible)
 {
     WTF_LOG(Media, "HTMLMediaElement::setClosedCaptionsVisible(%p, %s)", this, boolString(closedCaptionVisible));
 
     if (!m_player || !hasClosedCaptions())
         return;
 
     m_closedCaptionsVisible = closedCaptionVisible;
@@ skipping 410 matching lines @@
 
 #if ENABLE(WEB_AUDIO)
 void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
 {
     if (!visitor->isAlive(m_audioSourceNode) && audioSourceProvider())
         audioSourceProvider()->setClient(nullptr);
 }
 #endif
 
 }