Move initialization of ChromeURLRequestContexts to the IO thread.

chrome/test/testing_profile.h

Index: chrome/test/testing_profile.h
===================================================================
--- chrome/test/testing_profile.h	(revision 29872)
+++ chrome/test/testing_profile.h	(working copy)
@@ -74,7 +74,6 @@
   virtual void DestroyOffTheRecordProfile() {}
 
   virtual Profile* GetOriginalProfile() { return this; }
-  virtual ChromeAppCacheService* GetAppCacheService() { return NULL; }
   virtual VisitedLinkMaster* GetVisitedLinkMaster() { return NULL; }
   virtual ExtensionsService* GetExtensionsService() { return NULL; }
   virtual UserScriptMaster* GetUserScriptMaster() { return NULL; }
@@ -131,9 +130,11 @@
     InitThemes();
     return theme_provider_.get();
   }
-  virtual URLRequestContext* GetRequestContext() { return NULL; }
-  virtual URLRequestContext* GetRequestContextForMedia() { return NULL; }
-  virtual URLRequestContext* GetRequestContextForExtensions() { return NULL; }
+  virtual URLRequestContextGetter* GetRequestContext() { return NULL; }
+  virtual URLRequestContextGetter* GetRequestContextForMedia() { return NULL; }
+  virtual URLRequestContextGetter* GetRequestContextForExtensions() {
+      return NULL;
+  }
   virtual net::SSLConfigService* GetSSLConfigService() { return NULL; }
   virtual Blacklist* GetBlacklist() { return NULL; }
   void set_session_service(SessionService* session_service) {