Add the "virtual" keyword on method overrides that are missing it.

chrome/renderer/plugin_channel_host.h

 // Copyright (c) 2010 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_RENDERER_PLUGIN_CHANNEL_HOST_H_
 #define CHROME_RENDERER_PLUGIN_CHANNEL_HOST_H_
 #pragma once
 
 #include "base/hash_tables.h"
 #include "chrome/plugin/plugin_channel_base.h"
 
 class IsListeningFilter;
 class NPObjectBase;
 
 // Encapsulates an IPC channel between the renderer and one plugin process.
 // On the plugin side there's a corresponding PluginChannel.
 class PluginChannelHost : public PluginChannelBase {
  public:
   static PluginChannelHost* GetPluginChannelHost(
       const std::string& channel_name, MessageLoop* ipc_message_loop);
 
   virtual bool Init(MessageLoop* ipc_message_loop, bool create_pipe_now);
 
-  int GenerateRouteID();
+  virtual int GenerateRouteID();
 
   void AddRoute(int route_id, IPC::Channel::Listener* listener,
                 NPObjectBase* npobject);
   void RemoveRoute(int route_id);
 
   // IPC::Channel::Listener override
-  void OnChannelError();
+  virtual void OnChannelError();
 
   static void SetListening(bool flag);
 
   static bool IsListening();
 
   static void Broadcast(IPC::Message* message) {
     PluginChannelBase::Broadcast(message);
   }
 
   bool expecting_shutdown() { return expecting_shutdown_; }
 
  private:
   // Called on the render thread
   PluginChannelHost();
   ~PluginChannelHost();
 
   static PluginChannelBase* ClassFactory() { return new PluginChannelHost(); }
 
-  void OnControlMessageReceived(const IPC::Message& message);
+  virtual void OnControlMessageReceived(const IPC::Message& message);
   void OnSetException(const std::string& message);
   void OnPluginShuttingDown(const IPC::Message& message);
 
   // Keep track of all the registered WebPluginDelegeProxies to
   // inform about OnChannelError
   typedef base::hash_map<int, IPC::Channel::Listener*> ProxyMap;
   ProxyMap proxies_;
 
   // An IPC MessageFilter that can be told to filter out all messages. This is
   // used when the JS debugger is attached in order to avoid browser hangs.
   scoped_refptr<IsListeningFilter> is_listening_filter_;
 
   // True if we are expecting the plugin process to go away - in which case,
   // don't treat it as a crash.
   bool expecting_shutdown_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginChannelHost);
 };
 
 #endif  // CHROME_RENDERER_PLUGIN_CHANNEL_HOST_H_