content: Cleanup class/struct forward declarations

content/public/browser/render_process_host_factory.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_FACTORY_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_FACTORY_H_
 
 #include "content/common/content_export.h"
 
 namespace content {
 class BrowserContext;
-class ContentBrowserClient;
 class RenderProcessHost;
 class SiteInstance;
 
 // Factory object for RenderProcessHosts. Using this factory allows tests to
 // swap out a different one to use a TestRenderProcessHost.
 class RenderProcessHostFactory {
  public:
   virtual ~RenderProcessHostFactory() {}
   virtual RenderProcessHost* CreateRenderProcessHost(
       BrowserContext* browser_context,
       SiteInstance* site_instance) const = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_FACTORY_H_