Prevent a crash when visiting about:hang in two NTPs.

chrome/browser/dom_ui/dom_ui_factory.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_DOM_UI_DOM_UI_FACTORY_H_
 #define CHROME_BROWSER_DOM_UI_DOM_UI_FACTORY_H_
 #pragma once
 
 #include "chrome/browser/favicon_service.h"
 
@@ skipping 17 matching lines @@
   // given URL. This is useful for comparing the potential DOMUIs for two URLs.
   // Returns kNoDOMUI if the given URL will not use the DOM UI system.
   static DOMUITypeID GetDOMUIType(Profile* profile, const GURL& url);
 
   // Returns true if the given URL's scheme would trigger the DOM UI system.
   // This is a less precise test than UseDONUIForURL, which tells you whether
   // that specific URL matches a known one. This one is faster and can be used
   // to determine security policy.
   static bool HasDOMUIScheme(const GURL& url);
 
-  // Returns true if the given URL will use the DOM UI system.
+  // Returns true if the given URL must use the DOM UI system.
   static bool UseDOMUIForURL(Profile* profile, const GURL& url);
 
+  // Returns true if the given URL can be loaded by DOM UI system.  This
+  // includes URLs that can be loaded by normal tabs as well, such as
+  // javascript: URLs or about:hang.
+  static bool IsURLAcceptableForDOMUI(Profile* profile, const GURL& url);
+
   // Allocates a new DOMUI object for the given URL, and returns it. If the URL
   // is not a DOM UI URL, then it will return NULL. When non-NULL, ownership of
   // the returned pointer is passed to the caller.
   static DOMUI* CreateDOMUIForURL(TabContents* tab_contents, const GURL& url);
 
   // Get the favicon for |page_url| and forward the result to the |request|
   // when loaded.
   static void GetFaviconForURL(Profile* profile,
                                FaviconService::GetFaviconRequest* request,
                                const GURL& page_url);
 
  private:
   // Class is for scoping only.
   DOMUIFactory() {}
 
   // Gets the data for the favicon for a DOMUI page. Returns NULL if the DOMUI
   // does not have a favicon.
   static RefCountedMemory* GetFaviconResourceBytes(Profile* profile,
                                                    const GURL& page_url);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_DOM_UI_FACTORY_H_