Prerendered tabs use the same SessionStorage namespace as the tab that triggered the prerender.

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 e3c4ee210fb5eb7a01260a22482931935ebcfe26..b4432a326db2bb214f5e085860bd4b33365ed789 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -59,6 +59,7 @@ class PrerenderContents : public content::NotificationObserver,
     virtual PrerenderContents* CreatePrerenderContents(
         PrerenderManager* prerender_manager,
         PrerenderTracker* prerender_tracker,
+        SessionStorageNamespace* session_storage_namespace,

[mmenke, 2011/11/02 02:27:55]

nit:  Think we should forward declare this, as it's not clear where we're
currently pulling it in from.

         Profile* profile,
         const GURL& url,
         const GURL& referrer,
@@ -193,6 +194,7 @@ class PrerenderContents : public content::NotificationObserver,
  protected:
   PrerenderContents(PrerenderManager* prerender_manager,
                     PrerenderTracker* prerender_tracker,
+                    SessionStorageNamespace* session_storage_namespace,
                     Profile* profile,
                     const GURL& url,
                     const GURL& referrer,
@@ -234,6 +236,9 @@ class PrerenderContents : public content::NotificationObserver,
   // The prerender tracker tracking prerenders.
   PrerenderTracker* prerender_tracker_;
 
+  // The sessionStorage namespace of the tab that generated this prerender.
+  scoped_refptr<SessionStorageNamespace> session_storage_namespace_;
+
   // The URL being prerendered.
   GURL prerender_url_;