[blink] Support (semi-)transparent background colors in WebView/Frame.

third_party/WebKit/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 164 matching lines @@
 
   webFrameClient(frame).exitFullscreen();
 
   m_state = State::ExitingFullscreen;
 }
 
 void FullscreenController::fullscreenElementChanged(Element* fromElement,
                                                     Element* toElement) {
   DCHECK_NE(fromElement, toElement);
 
+  // Restore transparency if old fullscreen element changed it.
+  if (m_needsTransparencyRestore)
+    m_webViewImpl->setIsTransparent(m_initialTransparency);
+
   if (toElement) {
     DCHECK(Fullscreen::isCurrentFullScreenElement(*toElement));
 
     if (isHTMLVideoElement(*toElement)) {
       HTMLVideoElement& videoElement = toHTMLVideoElement(*toElement);
       videoElement.didEnterFullscreen();
 
       // If the video uses overlay fullscreen mode, make the background
       // transparent.
-      if (videoElement.usesOverlayFullscreenVideo() &&
-          m_webViewImpl->layerTreeView()) {
-        m_webViewImpl->layerTreeView()->setHasTransparentBackground(true);
+      if (videoElement.usesOverlayFullscreenVideo()) {
+        m_initialTransparency = m_webViewImpl->isTransparent();

[chrishtr, 2017/03/01 16:16:53]

For m_initialPageScaleFactor, it is "reset" in
FullscreenController::didUpdateLayout. Why is that done there and
your new value reset in fullscreenElementChanged?

[Eric Seckler, 2017/03/07 18:00:46]

This stuff changed a bit now, but I still restore within
fullscreenElementChanged. I added a few comments explaining why.

+        m_needsTransparencyRestore = true;
+        m_webViewImpl->setIsTransparent(true);
       }
     }
   }
 
   if (fromElement) {
     DCHECK(!Fullscreen::isCurrentFullScreenElement(*fromElement));
 
     if (isHTMLVideoElement(*fromElement)) {
-      // If the video used overlay fullscreen mode, restore the transparency.
-      if (m_webViewImpl->layerTreeView()) {
-        m_webViewImpl->layerTreeView()->setHasTransparentBackground(
-            m_webViewImpl->isTransparent());
-      }
-
       HTMLVideoElement& videoElement = toHTMLVideoElement(*fromElement);
       videoElement.didExitFullscreen();
     }
   }
 }
 
 void FullscreenController::updateSize() {
   DCHECK(m_webViewImpl->page());
 
   if (m_state != State::Fullscreen && m_state != State::ExitingFullscreen)
@@ skipping 46 matching lines @@
   // again to ensure the final constraints pick up the latest contents size.
   m_webViewImpl->didChangeContentsSize();
   if (m_webViewImpl->mainFrameImpl() &&
       m_webViewImpl->mainFrameImpl()->frameView())
     m_webViewImpl->mainFrameImpl()->frameView()->setNeedsLayout();
 
   m_webViewImpl->updateMainFrameLayoutSize();
 }
 
 }  // namespace blink