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

webkit/glue/plugins/pepper_file_ref.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 WEBKIT_GLUE_PLUGINS_PEPPER_FILE_REF_H_
 #define WEBKIT_GLUE_PLUGINS_PEPPER_FILE_REF_H_
 
 #include <string>
 
 #include "base/file_path.h"
@@ skipping 14 matching lines @@
           const std::string& validated_path);
   FileRef(PluginModule* module,
           const FilePath& external_file_path);
   virtual ~FileRef();
 
   // Returns a pointer to the interface implementing PPB_FileRef that is
   // exposed to the plugin.
   static const PPB_FileRef_Dev* GetInterface();
 
   // Resource overrides.
-  FileRef* AsFileRef() { return this; }
+  virtual FileRef* AsFileRef();
 
   // PPB_FileRef implementation.
   std::string GetName() const;
   scoped_refptr<FileRef> GetParent();
 
   // Returns the file system to which this FileRef belongs.
   scoped_refptr<FileSystem> GetFileSystem() const;
 
   // Returns the type of the file system to which this FileRef belongs.
   PP_FileSystemType_Dev GetFileSystemType() const;
 
   // Returns the virtual path (i.e., the path that the pepper plugin sees)
   // corresponding to this file.
   std::string GetPath() const;
 
   // Returns the system path corresponding to this file.
   FilePath GetSystemPath() const;
 
  private:
   scoped_refptr<FileSystem> file_system_;
   std::string virtual_path_;  // UTF-8 encoded
   FilePath system_path_;
 };
 
 }  // namespace pepper
 
 #endif  // WEBKIT_GLUE_PLUGINS_PEPPER_FILE_REF_H_