Use a hosted app's opener URL and not its origin to locate it.

content/public/browser/content_browser_client.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #pragma once
 
 #include <string>
 #include <utility>
@@ skipping 288 matching lines @@
   // Cancels a displayed desktop notification.
   virtual void CancelDesktopNotification(
       int render_process_id,
       int render_view_id,
       int notification_id) = 0;
 
   // Returns true if the given page is allowed to open a window of the given
   // type.
   // This is called on the IO thread.
   virtual bool CanCreateWindow(
+      const GURL& opener_url,
       const GURL& source_origin,
       WindowContainerType container_type,
       content::ResourceContext* context,
       int render_process_id) = 0;
 
   // Returns a title string to use in the task manager for a process host with
   // the given URL, or the empty string to fall back to the default logic.
   // This is called on the IO thread.
   virtual std::string GetWorkerProcessTitle(
       const GURL& url, content::ResourceContext* context) = 0;
@@ skipping 69 matching lines @@
   // This is called on a worker thread.
   virtual
       crypto::CryptoModuleBlockingPasswordDelegate* GetCryptoPasswordDelegate(
           const GURL& url) = 0;
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_