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

ppapi/proxy/truetype_font_singleton_resource.h

 // Copyright (c) 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_TRUETYPE_FONT_SINGLETON_RESOURCE_H_
 #define PPAPI_PROXY_TRUETYPE_FONT_SINGLETON_RESOURCE_H_
 
 #include <string>
 #include <vector>
 
 #include "ppapi/proxy/connection.h"
 #include "ppapi/proxy/plugin_resource.h"
 #include "ppapi/thunk/ppb_truetype_font_singleton_api.h"
 
 namespace ppapi {
 
 class TrackedCallback;
 
 namespace proxy {
 
 struct SerializedTrueTypeFontDesc;
 
 // This handles the singleton calls (that don't take a PP_Resource parameter)
 // on the TrueType font interface.
 class TrueTypeFontSingletonResource
     : public PluginResource,
       public thunk::PPB_TrueTypeFont_Singleton_API {
  public:
   TrueTypeFontSingletonResource(Connection connection, PP_Instance instance);
-  virtual ~TrueTypeFontSingletonResource();
+  ~TrueTypeFontSingletonResource() override;
 
   // Resource override.
-  virtual thunk::PPB_TrueTypeFont_Singleton_API*
-      AsPPB_TrueTypeFont_Singleton_API() override;
+  thunk::PPB_TrueTypeFont_Singleton_API* AsPPB_TrueTypeFont_Singleton_API()
+      override;
 
   // thunk::PPB_TrueTypeFont_Singleton_API implementation.
-  virtual int32_t GetFontFamilies(
+  int32_t GetFontFamilies(
       PP_Instance instance,
       const PP_ArrayOutput& output,
       const scoped_refptr<TrackedCallback>& callback) override;
-  virtual int32_t GetFontsInFamily(
+  int32_t GetFontsInFamily(
       PP_Instance instance,
       PP_Var family,
       const PP_ArrayOutput& output,
       const scoped_refptr<TrackedCallback>& callback) override;
 
  private:
   void OnPluginMsgGetFontFamiliesComplete(
       scoped_refptr<TrackedCallback> callback,
       PP_ArrayOutput array_output,
       const ResourceMessageReplyParams& params,
       const std::vector<std::string>& data);
   void OnPluginMsgGetFontsInFamilyComplete(
       scoped_refptr<TrackedCallback> callback,
       PP_ArrayOutput array_output,
       const ResourceMessageReplyParams& params,
       const std::vector<SerializedTrueTypeFontDesc>& fonts);
 
   DISALLOW_COPY_AND_ASSIGN(TrueTypeFontSingletonResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_TRUETYPE_FONT_SINGLETON_RESOURCE_H_