Expose the visibility state of a frame to the browser process.

content/public/browser/render_frame_host.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
+#include "third_party/WebKit/public/platform/WebPageVisibilityState.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/native_widget_types.h"
 #include "url/gurl.h"
 
 namespace base {
 class Value;
 }
 
 namespace content {
 class RenderProcessHost;
@@ skipping 68 matching lines @@
   // the result object on the page, navigating assistive technology to that
   // result.
   virtual void ActivateFindInPageResultForAccessibility(int request_id) = 0;
 
   // Temporary until we get rid of RenderViewHost.
   virtual RenderViewHost* GetRenderViewHost() = 0;
 
   // Returns the ServiceRegistry for this frame.
   virtual ServiceRegistry* GetServiceRegistry() = 0;
 
+  // Returns the visibility state of the frame. The different visibility states
+  // of a frame are defined in Blink.
+  virtual blink::WebPageVisibilityState GetVisibilityState() = 0;
+
  private:
   // This interface should only be implemented inside content.
   friend class RenderFrameHostImpl;
   RenderFrameHost() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_FRAME_HOST_H_