Modify prerendering to support having multiple session storage namespaces per tab.

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index bd0de98ea5c5f5a66f1d034a6fbf585128aacb4c..40f6c3e2fd02626bb3e74ac1df5a60be7ed3cba3 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -113,7 +113,7 @@ class PrerenderContents : public content::NotificationObserver,
   virtual void StartPrerendering(
       int creator_child_id,
       const gfx::Size& size,
-      content::SessionStorageNamespace* session_storage_namespace,
+      const content::SessionStorageNamespaceMap& session_storage_namespace_map,
       bool is_control_group);
 
   // Verifies that the prerendering is not using too many resources, and kills
@@ -161,7 +161,8 @@ class PrerenderContents : public content::NotificationObserver,
   // |url| and |session_storage_namespace|.
   bool Matches(
       const GURL& url,
-      const content::SessionStorageNamespace* session_storage_namespace) const;
+      const content::SessionStorageNamespaceMap& session_storage_namespace_map)
+          const;
 
   // content::WebContentsObserver implementation.
   virtual void DidStopLoading(
@@ -247,6 +248,9 @@ class PrerenderContents : public content::NotificationObserver,
     gfx::Size size;
   };
 
+  // TODO(ajwong): These protected virtuals are only around for unittests. Make
+  // them private.
+
   PrerenderContents(PrerenderManager* prerender_manager,
                     PrerenderTracker* prerender_tracker,
                     Profile* profile,
@@ -273,7 +277,8 @@ class PrerenderContents : public content::NotificationObserver,
   }
 
   virtual content::WebContents* CreateWebContents(
-      content::SessionStorageNamespace* session_storage_namespace);
+      const content::SessionStorageNamespaceMap&
+          session_storage_namespace_map);
 
   bool prerendering_has_started_;
 
@@ -330,10 +335,10 @@ class PrerenderContents : public content::NotificationObserver,
   // such as HTTP redirects or javascript redirects.
   std::vector<GURL> alias_urls_;
 
-  // The session storage namespace id for use in matching. We must save it
+  // The session storage namespace ids for use in matching. We must save it
   // rather than get it from the RenderViewHost since in the control group
   // we won't have a RenderViewHost.
-  int64 session_storage_namespace_id_;
+  std::set<int64> session_storage_namespace_ids_;
 
   bool has_stopped_loading_;