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 379 matching lines @@
 
   // Tears down the browser-side state relating to the Mojo connection between
   // this instance and its associated render frame.
   void InvalidateMojoConnection();
 
   // Returns whether the frame is focused. A frame is considered focused when it
   // is the focused frame within its frame tree and its associated
   // RenderWidgetHost is also focused.
   bool IsFocused() const;
 
+  // Returns the visibility state of the frame. The different visibility states
+  // of a frame a define in Blink.

[Charlie Reis, 2015/01/22 21:03:55]

nit: are defined

[mlamouri (slow - plz ping), 2015/01/23 12:32:58]

Sorry for those typos :(

+  blink::WebPageVisibilityState GetVisibilityState();
+
  protected:
   friend class RenderFrameHostFactory;
 
   // |flags| is a combination of CreateRenderFrameFlags.
   // TODO(nasko): Remove dependency on RenderViewHost here. RenderProcessHost
   // should be the abstraction needed here, but we need RenderViewHost to pass
   // into WebContentsObserver::FrameDetached for now.
   RenderFrameHostImpl(RenderViewHostImpl* render_view_host,
                       RenderFrameHostDelegate* delegate,
                       FrameTree* frame_tree,
@@ skipping 222 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_