Support subtitles for native fullscreen video

Source/core/rendering/RenderLayerBacking.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 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 496 matching lines @@
     if (RuntimeEnabledFeatures::cssCompositingEnabled())
         updateLayerBlendMode(renderer()->style());
 
     bool isSimpleContainer = isSimpleContainerCompositingLayer();
 
     m_owningLayer->updateDescendantDependentFlags();
 
     // m_graphicsLayer is the corresponding GraphicsLayer for this RenderLayer and its non-compositing
     // descendants. So, the visibility flag for m_graphicsLayer should be true if there are any
     // non-compositing visible layers.
-    m_graphicsLayer->setContentsVisible(m_owningLayer->hasVisibleContent() || hasVisibleNonCompositingDescendantLayers());
+    bool contentsVisible = m_owningLayer->hasVisibleContent() || hasVisibleNonCompositingDescendantLayers();
+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && renderer()->isVideo()) {
+        HTMLMediaElement* mediaElement = toHTMLMediaElement(renderer()->node());
+        if (mediaElement->isFullscreen())
+            contentsVisible = false;
+    }
+    m_graphicsLayer->setContentsVisible(contentsVisible);
 
     RenderStyle* style = renderer()->style();
     // FIXME: reflections should force transform-style to be flat in the style: https://bugs.webkit.org/show_bug.cgi?id=106959
     bool preserves3D = style->transformStyle3D() == TransformStyle3DPreserve3D && !renderer()->hasReflection();
     m_graphicsLayer->setPreserves3D(preserves3D);
     m_graphicsLayer->setBackfaceVisibility(style->backfaceVisibility() == BackfaceVisibilityVisible);
 
     RenderLayer* compAncestor = m_owningLayer->ancestorCompositingLayer();
 
     // We compute everything relative to the enclosing compositing layer.
@@ skipping 1351 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore