Update {virtual,override} to follow C++11 style in ppapi.

ppapi/proxy/printing_resource.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 PPAPI_PROXY_PRINTING_RESOURCE_H_
 #define PPAPI_PROXY_PRINTING_RESOURCE_H_
 
 #include "ppapi/proxy/connection.h"
 #include "ppapi/proxy/plugin_resource.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 #include "ppapi/shared_impl/tracked_callback.h"
 #include "ppapi/thunk/ppb_printing_api.h"
 
 namespace ppapi {
 namespace proxy {
 
 class PPAPI_PROXY_EXPORT PrintingResource
     : public PluginResource,
       public NON_EXPORTED_BASE(thunk::PPB_Printing_API) {
  public:
   PrintingResource(Connection connection,
                    PP_Instance instance);
-  virtual ~PrintingResource();
+  ~PrintingResource() override;
 
   // Resource overrides.
-  virtual thunk::PPB_Printing_API* AsPPB_Printing_API() override;
+  thunk::PPB_Printing_API* AsPPB_Printing_API() override;
 
   // PPB_Printing_API.
-  virtual int32_t GetDefaultPrintSettings(
+  int32_t GetDefaultPrintSettings(
       PP_PrintSettings_Dev* print_settings,
       scoped_refptr<TrackedCallback> callback) override;
 
  private:
   void OnPluginMsgGetDefaultPrintSettingsReply(
       PP_PrintSettings_Dev* settings_out,
       scoped_refptr<TrackedCallback> callback,
       const ResourceMessageReplyParams& params,
       const PP_PrintSettings_Dev& settings);
 
   DISALLOW_COPY_AND_ASSIGN(PrintingResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PRINTING_RESOURCE_H_