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

webkit/glue/plugins/pepper_url_response_info.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_URL_RESPONSE_INFO_H_
 #define WEBKIT_GLUE_PLUGINS_PEPPER_URL_RESPONSE_INFO_H_
 
 #include <string>
 
 #include "ppapi/c/ppb_url_response_info.h"
 #include "webkit/glue/plugins/pepper_resource.h"
 
 namespace WebKit {
 class WebURLResponse;
 }
 
 namespace pepper {
 
 class URLResponseInfo : public Resource {
  public:
   explicit URLResponseInfo(PluginModule* module);
   virtual ~URLResponseInfo();
 
   // Returns a pointer to the interface implementing PPB_URLResponseInfo that
   // is exposed to the plugin.
   static const PPB_URLResponseInfo* GetInterface();
 
   // Resource overrides.
-  URLResponseInfo* AsURLResponseInfo() { return this; }
+  virtual URLResponseInfo* AsURLResponseInfo();
 
   // PPB_URLResponseInfo implementation.
   PP_Var GetProperty(PP_URLResponseProperty property);
 
   bool Initialize(const WebKit::WebURLResponse& response);
 
   FileRef* body() { return body_; }
 
   std::string redirect_url() { return redirect_url_; }
 
  private:
   std::string url_;
   std::string headers_;
   int32_t status_code_;
   std::string status_text_;
   std::string redirect_url_;
   scoped_refptr<FileRef> body_;
 };
 
 }  // namespace pepper
 
 #endif  // WEBKIT_GLUE_PLUGINS_PEPPER_URL_RESPONSE_INFO_H_