Browser Plugin: Implement CanGoBack/CanGoForward

content/renderer/browser_plugin/browser_plugin_manager_impl.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_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_
 #define CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_
 
 #include "content/renderer/browser_plugin/browser_plugin_manager.h"
 #include "googleurl/src/gurl.h"
 
@@ skipping 29 matching lines @@
                    const GURL& url,
                    bool is_top_level);
   void OnLoadAbort(int instance_id,
                    const GURL& url,
                    bool is_top_level,
                    const std::string& type);
   void OnLoadRedirect(int instance_id,
                       const GURL& old_url,
                       const GURL& new_url,
                       bool is_top_level);
+  void OnNavigationStateUpdate(int instance_id,
+                               int current_entry_index,
+                               int entry_count);
 
   DISALLOW_COPY_AND_ASSIGN(BrowserPluginManagerImpl);
 };
 
 }  // namespace content
 
 #endif //  CONTENT_RENDERER_BROWSER_PLUGIN_BROWSER_PLUGIN_MANAGER_IMPL_H_