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

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index a45399ec4245e8c283c4919377bf3bece0f974c0..cad0a849602c8a05678180086539d16ecf56572b 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -2605,6 +2605,22 @@ ChromeContentBrowserClient::OverrideCookieStoreForRenderProcess(
                                  render_process_id).get();
 }
 
+bool ChromeContentBrowserClient::IsPrerendering(
+    content::RenderFrameHost* render_frame_host) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  WebContents* web_contents =
+      WebContents::FromRenderFrameHost(render_frame_host);
+  DCHECK(web_contents);
+
+  Profile* profile =
+      Profile::FromBrowserContext(web_contents->GetBrowserContext());
+  prerender::PrerenderManager* prerender_manager =
+      prerender::PrerenderManagerFactory::GetForProfile(profile);
+  return prerender_manager &&
+         prerender_manager->IsWebContentsPrerendering(web_contents, nullptr);
+}
+
 #if defined(ENABLE_WEBRTC)
 void ChromeContentBrowserClient::MaybeCopyDisableWebRtcEncryptionSwitch(
     base::CommandLine* to_command_line,