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

third_party/WebKit/Source/web/FullscreenController.h

 /*
  * 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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef FullscreenController_h
 #define FullscreenController_h
 
+#include <memory>
+
 #include "platform/geometry/FloatPoint.h"
 #include "platform/geometry/IntSize.h"
-#include <memory>
+#include "platform/graphics/Color.h"
 
 namespace blink {
 
 class Element;
 class LocalFrame;
 class WebViewImpl;
 
 class FullscreenController {
  public:
   static std::unique_ptr<FullscreenController> create(WebViewImpl*);
@@ skipping 17 matching lines @@
 
   void updateSize();
 
   void didUpdateLayout();
 
  protected:
   explicit FullscreenController(WebViewImpl*);
 
  private:
   void updatePageScaleConstraints(bool removeConstraints);
+  void restoreBackgroundColorOverride();
 
   WebViewImpl* m_webViewImpl;
 
   // State is used to avoid unnecessary enter/exit requests, and to restore the
   // m_initial* after the first layout upon exiting fullscreen. Typically, the
   // state goes through every state from Initial to NeedsScrollAndScaleRestore
   // and then back to Initial, but the are two exceptions:
   //  1. didExitFullscreen() can transition from any non-Initial state to
   //     NeedsScrollAndScaleRestore, in case of a browser-intiated exit.
   //  2. enterFullscreen() can transition from NeedsScrollAndScaleRestore to
   //     EnteringFullscreen, in case of a quick exit+enter.
   enum class State {
     Initial,
     EnteringFullscreen,
     Fullscreen,
     ExitingFullscreen,
     NeedsScrollAndScaleRestore
   };
   State m_state = State::Initial;
 
   float m_initialPageScaleFactor = 0.0f;
   IntSize m_initialScrollOffset;
   FloatPoint m_initialVisualViewportOffset;
+  bool m_initialBackgroundColorOverrideEnabled = false;
+  RGBA32 m_initialBackgroundColorOverride = Color::transparent;
 };
 
 }  // namespace blink
 
 #endif