Add setVisibilityState API to WebFrameWidget

Source/web/WebFrameWidgetImpl.h

 /*
  * Copyright (C) 2014 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 116 matching lines @@
 
     // Returns the currently focused Element or null if no element has focus.
     Element* focusedElement() const;
 
     void scheduleAnimation();
 
     LayerCompositor* compositor() const;
     void suppressInvalidations(bool enable);
     void setRootGraphicsLayer(GraphicsLayer*);
 
+    void setVisibilityState(WebPageVisibilityState, bool) override;
+
     // Exposed for the purpose of overriding device metrics.
     void sendResizeEventAndRepaint();
 
     void updateMainFrameLayoutSize();
 
     // Returns the page object associated with this widget. This may be null when
     // the page is shutting down, but will be valid at all other times.
     Page* page() const { return m_page; }
 
     // Returns true if the event leads to scrolling.
@@ skipping 59 matching lines @@
     bool m_suppressNextKeypressEvent;
 
     bool m_ignoreInputEvents;
 
     static const WebInputEvent* m_currentInputEvent;
 };
 
 } // namespace blink
 
 #endif