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

content/public/browser/content_browser_client.h

 // Copyright (c) 2012 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_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 570 matching lines @@
   // camera. Note that this does not query the user. |type| must be
   // MEDIA_DEVICE_AUDIO_CAPTURE or MEDIA_DEVICE_VIDEO_CAPTURE.
   virtual bool CheckMediaAccessPermission(BrowserContext* browser_context,
                                           const GURL& security_origin,
                                           MediaStreamType type);
 
   // Allows to override browser Mojo services exposed through the
   // RenderProcessHost.
   virtual void OverrideRenderProcessMojoServices(ServiceRegistry* registry) {}
 
+  // Return whether the given a given frame is being prerendered.
+  virtual bool IsPrerendering(RenderFrameHost* render_frame_host);

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

Prerendering is not a concept in content/, so we should name this something
else.  Are you just trying to get the ContentBrowserClient to participate in the
decision about visibility?

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

Oh, ok. I was wondering why ContentRenderClient wasn't explicit about
"prerender" status. I am a bit surprised that content/ doesn't know about
prerendering given that blink/ has a WebPageVisibilityPrerender status and we
need content/ to set that I guess.
Anyway, I will mirror this to what ContentRenderClient does then.

+
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   // Populates |mappings| with all files that need to be mapped before launching
   // a child process.
   virtual void GetAdditionalMappedFilesForChildProcess(
       const base::CommandLine& command_line,
       int child_process_id,
       FileDescriptorInfo* mappings) {}
 #endif
 
 #if defined(OS_WIN)
@@ skipping 11 matching lines @@
   // Allows an embedder to provide its own ExternalVideoSurfaceContainer
   // implementation.  Return nullptr to disable external surface video.
   virtual ExternalVideoSurfaceContainer*
   OverrideCreateExternalVideoSurfaceContainer(WebContents* web_contents);
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_