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

ppapi/proxy/platform_verification_private_resource.h

 // Copyright 2013 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_PLATFORM_VERIFICATION_PRIVATE_RESOURCE_H_
 #define PPAPI_PROXY_PLATFORM_VERIFICATION_PRIVATE_RESOURCE_H_
 
 #include "ppapi/proxy/plugin_resource.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 #include "ppapi/thunk/ppb_platform_verification_api.h"
 
 namespace ppapi {
 namespace proxy {
 
 class PPAPI_PROXY_EXPORT PlatformVerificationPrivateResource
     : public PluginResource,
       public thunk::PPB_PlatformVerification_API {
  public:
   PlatformVerificationPrivateResource(Connection connection,
                                       PP_Instance instance);
 
  private:
   struct ChallengePlatformParams {
     PP_Var* signed_data;
     PP_Var* signed_data_signature;
     PP_Var* platform_key_certificate;
     scoped_refptr<TrackedCallback> callback;
   };
 
-  virtual ~PlatformVerificationPrivateResource();
+  ~PlatformVerificationPrivateResource() override;
 
   // PluginResource overrides.
-  virtual thunk::PPB_PlatformVerification_API*
-      AsPPB_PlatformVerification_API() override;
+  thunk::PPB_PlatformVerification_API* AsPPB_PlatformVerification_API()
+      override;
 
   // PPB_PlatformVerification_API implementation.
-  virtual int32_t ChallengePlatform(
+  int32_t ChallengePlatform(
       const PP_Var& service_id,
       const PP_Var& challenge,
       PP_Var* signed_data,
       PP_Var* signed_data_signature,
       PP_Var* platform_key_certificate,
       const scoped_refptr<TrackedCallback>& callback) override;
   void OnChallengePlatformReply(
       ChallengePlatformParams output_params,
       const ResourceMessageReplyParams& params,
       const std::vector<uint8_t>& raw_signed_data,
       const std::vector<uint8_t>& raw_signed_data_signature,
       const std::string& raw_platform_key_certificate);
 
   DISALLOW_COPY_AND_ASSIGN(PlatformVerificationPrivateResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PLATFORM_VERIFICATION_PRIVATE_RESOURCE_H_