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

chrome/browser/autocomplete/autocomplete_edit.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/autocomplete/autocomplete_edit.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/metrics/histogram.h"
@@ skipping 20 matching lines @@
 #include "chrome/browser/search_engines/template_url.h"
 #include "chrome/browser/search_engines/template_url_prepopulate_data.h"
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/omnibox/omnibox_view.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
+#include "content/browser/renderer_host/render_view_host.h"
 #include "content/browser/user_metrics.h"
 #include "content/public/browser/notification_service.h"
 #include "googleurl/src/gurl.h"
 #include "googleurl/src/url_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 // AutocompleteEditController
 
 AutocompleteEditController::~AutocompleteEditController() {
@@ skipping 979 matching lines @@
 }
 
 void AutocompleteEditModel::DoPrerender(const AutocompleteMatch& match) {
   // Do not prerender if the destination URL is the same as the current URL.
   if (match.destination_url == PermanentURL())
     return;
   if (user_input_in_progress() && popup_->IsOpen()) {
     TabContentsWrapper* tab = controller_->GetTabContentsWrapper();
     prerender::PrerenderManager* prerender_manager =
         prerender::PrerenderManagerFactory::GetForProfile(tab->profile());
-    if (prerender_manager)
-      prerender_manager->AddPrerenderFromOmnibox(match.destination_url);
+    if (prerender_manager) {
+      RenderViewHost* current_host = tab->tab_contents()->render_view_host();
+      if (current_host) {

[Peter Kasting, 2011/11/02 17:53:56]

Can this actually be NULL (maybe for about:blank)?  If not we shouldn't have the
conditional check.

[cbentzel, 2011/11/02 18:14:14]

There's two periods during the TabContents constructor and destructor where it
can be NULL, but not at this point. I'll remove the check. Thanks.

+        prerender_manager->AddPrerenderFromOmnibox(
+            match.destination_url, current_host->session_storage_namespace());
+      }
+    }
   }
 }
 
 void AutocompleteEditModel::DoPreconnect(const AutocompleteMatch& match) {
   if (!match.destination_url.SchemeIs(chrome::kExtensionScheme)) {
     // Warm up DNS Prefetch cache, or preconnect to a search service.
     UMA_HISTOGRAM_ENUMERATION("Autocomplete.MatchType", match.type,
                               AutocompleteMatch::NUM_TYPES);
     if (profile_->GetNetworkPredictor()) {
       profile_->GetNetworkPredictor()->AnticipateOmniboxUrl(
           match.destination_url,
           NetworkActionPredictor::IsPreconnectable(match));
     }
     // We could prefetch the alternate nav URL, if any, but because there
     // can be many of these as a user types an initial series of characters,
     // the OS DNS cache could suffer eviction problems for minimal gain.
   }
 }
 
 //  static
 bool AutocompleteEditModel::IsSpaceCharForAcceptingKeyword(wchar_t c) {
   switch (c) {
     case 0x0020:  // Space
     case 0x3000:  // Ideographic Space
       return true;
     default:
       return false;
   }
 }