Only commit cookie changes in prerenders after a prerender is shown

chrome/browser/chrome_content_browser_client.h

Index: chrome/browser/chrome_content_browser_client.h
===================================================================
--- chrome/browser/chrome_content_browser_client.h	(revision 265252)
+++ chrome/browser/chrome_content_browser_client.h	(working copy)
@@ -31,6 +31,10 @@
 class BrowserPermissionsPolicyDelegate;
 }
 
+namespace prerender {
+class PrerenderTracker;
+}
+
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
@@ -102,6 +106,7 @@
                                   const GURL& url) OVERRIDE;
   virtual bool IsSuitableHost(content::RenderProcessHost* process_host,
                               const GURL& site_url) OVERRIDE;
+  virtual bool MayReuseHost(content::RenderProcessHost* process_host) OVERRIDE;
   virtual bool ShouldTryToUseExistingProcessHost(
       content::BrowserContext* browser_context, const GURL& url) OVERRIDE;
   virtual void SiteInstanceGotProcess(
@@ -282,6 +287,9 @@
 
   virtual bool IsPluginAllowedToUseDevChannelAPIs() OVERRIDE;
 
+  virtual net::CookieStore* OverrideCookieStoreForRenderProcess(
+      int render_process_id) OVERRIDE;
+
  private:
 #if defined(ENABLE_WEBRTC)
   // Copies disable WebRTC encryption switch depending on the channel.
@@ -300,6 +308,13 @@
   scoped_ptr<extensions::BrowserPermissionsPolicyDelegate>
       permissions_policy_delegate_;
 
+  // The prerender tracker used to determine whether a render process is used
+  // for prerendering and an override cookie store must be provided.
+  // This needs to be kept as a member rather than just looked up from
+  // the profile due to initialization ordering, as well as due to threading
+  // (initialize on the UI thread, use on the IO thread).

[Charlie Reis, 2014/05/07 17:21:32]

What makes this safe to use on a different thread than it's initialized? 
(Otherwise it could be partially initialized when we try to use it.)  

Can you clarify that in the comment?

[tburkard, 2014/05/07 18:34:27]

Corrected & clarified the comment.

+  prerender::PrerenderTracker* prerender_tracker_;
+
   friend class DisableWebRtcEncryptionFlagTest;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentBrowserClient);