chrome: Cleanup class/struct forward declarations

chrome/browser/prerender/prerender_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 CHROME_BROWSER_PRERENDER_PRERENDER_CONTENTS_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_CONTENTS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 26 matching lines @@
 class SessionStorageNamespace;
 class WebContents;
 }
 
 namespace history {
 struct HistoryAddPageArgs;
 }
 
 namespace prerender {
 
-class PrerenderHandle;
 class PrerenderManager;
 class PrerenderResourceThrottle;
 
 class PrerenderContents : public content::NotificationObserver,
                           public content::WebContentsObserver {
  public:
   // PrerenderContents::Create uses the currently registered Factory to create
   // the PrerenderContents. Factory is intended for testing.
   class Factory {
    public:
@@ skipping 309 matching lines @@
   // A running tally of the number of bytes this prerender has caused to be
   // transferred over the network for resources.  Updated with AddNetworkBytes.
   int64_t network_bytes_;
 
   DISALLOW_COPY_AND_ASSIGN(PrerenderContents);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_CONTENTS_H_