Let the WebMediaPlayer decide whether to use overlay video.

Source/web/FullscreenController.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 67 matching lines @@
 
         updatePageScaleConstraints(false);
         m_webViewImpl->setPageScaleFactor(1.0f);
         m_webViewImpl->mainFrame()->setScrollOffset(WebSize());
         m_webViewImpl->setVisualViewportOffset(FloatPoint());
     }
 
     Fullscreen::from(document).didEnterFullScreenForElement(element.get());
     ASSERT(Fullscreen::currentFullScreenElementFrom(document) == element);
 
-    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled()) {
-        if (isHTMLVideoElement(element)) {
-            HTMLVideoElement* videoElement = toHTMLVideoElement(element);
-            if (HTMLMediaElement::isMediaStreamURL(videoElement->sourceURL().string()))
-                return;
+    if (isHTMLVideoElement(element)) {
+        HTMLVideoElement* videoElement = toHTMLVideoElement(element);
+        if (videoElement->usesOverlayFullscreenVideo()) {
             if (videoElement->webMediaPlayer()
                 // FIXME: There is no embedder-side handling in layout test mode.
                 && !LayoutTestSupport::isRunningLayoutTest()) {
                 videoElement->webMediaPlayer()->enterFullscreen();
             }
             if (m_webViewImpl->layerTreeView())
                 m_webViewImpl->layerTreeView()->setHasTransparentBackground(true);
         }
     }
 }
@@ skipping 93 matching lines @@
 }
 
 DEFINE_TRACE(FullscreenController)
 {
     visitor->trace(m_provisionalFullScreenElement);
     visitor->trace(m_fullScreenFrame);
 }
 
 } // namespace blink