Standardize usage of virtual/override/final in gpu/

gpu/command_buffer/client/gl_in_process_context.cc

Index: gpu/command_buffer/client/gl_in_process_context.cc
diff --git a/gpu/command_buffer/client/gl_in_process_context.cc b/gpu/command_buffer/client/gl_in_process_context.cc
index e8771191b3dd9a729d5aac4951dacb9a7876f2c9..7f24bd64a024da264b48e11aa24e3a61a26f180f 100644
--- a/gpu/command_buffer/client/gl_in_process_context.cc
+++ b/gpu/command_buffer/client/gl_in_process_context.cc
@@ -48,7 +48,7 @@ class GLInProcessContextImpl
  public:
   explicit GLInProcessContextImpl(
       const GLInProcessContextSharedMemoryLimits& mem_limits);
-  virtual ~GLInProcessContextImpl();
+  ~GLInProcessContextImpl() override;
 
   bool Initialize(
       scoped_refptr<gfx::GLSurface> surface,
@@ -62,9 +62,9 @@ class GLInProcessContextImpl
       const scoped_refptr<InProcessCommandBuffer::Service>& service);
 
   // GLInProcessContext implementation:
-  virtual void SetContextLostCallback(const base::Closure& callback) override;
-  virtual gles2::GLES2Implementation* GetImplementation() override;
-  virtual size_t GetMappedMemoryLimit() override;
+  void SetContextLostCallback(const base::Closure& callback) override;
+  gles2::GLES2Implementation* GetImplementation() override;
+  size_t GetMappedMemoryLimit() override;
 
 #if defined(OS_ANDROID)
   virtual scoped_refptr<gfx::SurfaceTexture> GetSurfaceTexture(