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

ppapi/proxy/ppb_buffer_proxy.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_PPB_BUFFER_PROXY_H_
 #define PPAPI_PROXY_PPB_BUFFER_PROXY_H_
 
 #include "base/memory/shared_memory.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/thunk/ppb_buffer_api.h"
 
 namespace ppapi {
 
 class HostResource;
 
 namespace proxy {
 
 class SerializedHandle;
 
 class Buffer : public thunk::PPB_Buffer_API, public Resource {
  public:
   Buffer(const HostResource& resource,
          const base::SharedMemoryHandle& shm_handle,
          uint32_t size);
-  virtual ~Buffer();
+  ~Buffer() override;
 
   // Resource overrides.
-  virtual thunk::PPB_Buffer_API* AsPPB_Buffer_API() override;
+  thunk::PPB_Buffer_API* AsPPB_Buffer_API() override;
 
   // PPB_Buffer_API implementation.
-  virtual PP_Bool Describe(uint32_t* size_in_bytes) override;
-  virtual PP_Bool IsMapped() override;
-  virtual void* Map() override;
-  virtual void Unmap() override;
+  PP_Bool Describe(uint32_t* size_in_bytes) override;
+  PP_Bool IsMapped() override;
+  void* Map() override;
+  void Unmap() override;
 
   // Trusted
-  virtual int32_t GetSharedMemory(int* handle) override;
+  int32_t GetSharedMemory(int* handle) override;
 
  private:
   base::SharedMemory shm_;
   uint32_t size_;
   int map_count_;
 
   DISALLOW_COPY_AND_ASSIGN(Buffer);
 };
 
 class PPB_Buffer_Proxy : public InterfaceProxy {
@@ skipping 17 matching lines @@
   void OnMsgCreate(PP_Instance instance,
                    uint32_t size,
                    HostResource* result_resource,
                    ppapi::proxy::SerializedHandle* result_shm_handle);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_BUFFER_PROXY_H_