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

ppapi/proxy/compositor_resource.h

 // Copyright 2014 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_COMPOSITOR_RESOURCE_H_
 #define PPAPI_PROXY_COMPOSITOR_RESOURCE_H_
 
 #include <map>
 
 #include "ppapi/proxy/compositor_layer_resource.h"
@@ skipping 10 matching lines @@
       public thunk::PPB_Compositor_API {
  public:
   CompositorResource(Connection connection,
                      PP_Instance instance);
 
   bool IsInProgress() const;
 
   int32_t GenerateResourceId() const;
 
  private:
-  virtual ~CompositorResource();
+  ~CompositorResource() override;
 
   // Resource overrides:
-  virtual thunk::PPB_Compositor_API* AsPPB_Compositor_API() override;
+  thunk::PPB_Compositor_API* AsPPB_Compositor_API() override;
 
   // PluginResource overrides:
-  virtual void OnReplyReceived(const ResourceMessageReplyParams& params,
-                               const IPC::Message& msg) override;
+  void OnReplyReceived(const ResourceMessageReplyParams& params,
+                       const IPC::Message& msg) override;
 
   // thunk::PPB_Compositor_API overrides:
-  virtual PP_Resource AddLayer() override;
-  virtual int32_t CommitLayers(
-      const scoped_refptr<TrackedCallback>& callback) override;
-  virtual int32_t ResetLayers() override;
+  PP_Resource AddLayer() override;
+  int32_t CommitLayers(const scoped_refptr<TrackedCallback>& callback) override;
+  int32_t ResetLayers() override;
 
   // IPC msg handlers:
   void OnPluginMsgCommitLayersReply(const ResourceMessageReplyParams& params);
   void OnPluginMsgReleaseResource(
       const ResourceMessageReplyParams& params,
       int32_t id,
       uint32_t sync_point,
       bool is_lost);
 
   void ResetLayersInternal(bool is_aborted);
@@ skipping 16 matching lines @@
   // The last resource id for texture or image.
   mutable int32_t last_resource_id_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorResource);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_COMPOSITOR_RESOURCE_H_