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

chrome/browser/plugin_process_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_BROWSER_PLUGIN_PROCESS_HOST_H_
 #define CHROME_BROWSER_PLUGIN_PROCESS_HOST_H_
 #pragma once
 
 #include "build/build_config.h"
 
@@ skipping 48 matching lines @@
   };
 
   PluginProcessHost();
   virtual ~PluginProcessHost();
 
   // Initialize the new plugin process, returning true on success. This must
   // be called before the object can be used.
   bool Init(const WebPluginInfo& info, const std::string& locale);
 
   // Force the plugin process to shutdown (cleanly).
-  void ForceShutdown();
+  virtual void ForceShutdown();
 
   virtual void OnMessageReceived(const IPC::Message& msg);
   virtual void OnChannelConnected(int32 peer_pid);
   virtual void OnChannelError();
 
   // ResolveProxyMsgHelper::Delegate implementation:
   virtual void OnResolveProxyCompleted(IPC::Message* reply_msg,
                                        int result,
                                        const std::string& proxy_list);
 
@@ skipping 95 matching lines @@
   // Tracks modal windows currently visible.
   std::set<uint32> plugin_modal_windows_set_;
   // Tracks the current visibility of the cursor.
   bool plugin_cursor_visible_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(PluginProcessHost);
 };
 
 #endif  // CHROME_BROWSER_PLUGIN_PROCESS_HOST_H_