Prerendered pages are swapped in at browser::Navigate time.

content/public/browser/web_contents.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_WEB_CONTENTS_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/process_util.h"
@@ skipping 347 matching lines @@
   // locked.
   virtual bool GotResponseToLockMouseRequest(bool allowed) = 0;
 
   // Returns true if the location bar should be focused by default rather than
   // the page contents. The view calls this function when the tab is focused
   // to see what it should do.
   virtual bool FocusLocationBarByDefault() = 0;
 
   // Focuses the location bar.
   virtual void SetFocusToLocationBar(bool select_all) = 0;
+
+  // Get the origin of the opener.
+  virtual const GURL& GetOpenerOrigin() const = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_