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

content/browser/frame_host/render_frame_host_impl.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_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 119 matching lines @@
   bool IsCrossProcessSubframe() override;
   GURL GetLastCommittedURL() override;
   gfx::NativeView GetNativeView() override;
   void ExecuteJavaScript(const base::string16& javascript) override;
   void ExecuteJavaScript(const base::string16& javascript,
                          const JavaScriptResultCallback& callback) override;
   void ExecuteJavaScriptForTests(const base::string16& javascript) override;
   void ActivateFindInPageResultForAccessibility(int request_id) override;
   RenderViewHost* GetRenderViewHost() override;
   ServiceRegistry* GetServiceRegistry() override;
+  blink::WebPageVisibilityState GetVisibilityState() override;
 
   // IPC::Sender
   bool Send(IPC::Message* msg) override;
 
   // IPC::Listener
   bool OnMessageReceived(const IPC::Message& msg) override;
 
   // BrowserAccessibilityDelegate
   void AccessibilitySetFocus(int acc_obj_id) override;
   void AccessibilityDoDefaultAction(int acc_obj_id) override;
@@ skipping 504 matching lines @@
 
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_