Only commit cookie changes in prerenders after a prerender is shown

chrome/browser/profiles/profile_io_data.h

Index: chrome/browser/profiles/profile_io_data.h
===================================================================
--- chrome/browser/profiles/profile_io_data.h	(revision 269838)
+++ chrome/browser/profiles/profile_io_data.h	(working copy)
@@ -61,6 +61,10 @@
 class URLBlacklistManager;
 }  // namespace policy
 
+namespace prerender {
+class PrerenderTracker;
+}
+
 // Conceptually speaking, the ProfileIOData represents data that lives on the IO
 // thread that is owned by a Profile, such as, but not limited to, network
 // objects like CookieMonster, HttpTransactionFactory, etc.  Profile owns
@@ -298,6 +302,8 @@
     // ensure it's not accidently used on the IO thread. Before using it on the
     // UI thread, call ProfileManager::IsValidProfile to ensure it's alive.
     void* profile;
+
+    prerender::PrerenderTracker* prerender_tracker;
   };
 
   explicit ProfileIOData(Profile::ProfileType profile_type);