Standardize usage of virtual/override/final in content/

content/common/gpu/null_transport_surface.h

Index: content/common/gpu/null_transport_surface.h
diff --git a/content/common/gpu/null_transport_surface.h b/content/common/gpu/null_transport_surface.h
index c4937e39a828e5244208d6766549bbcfbc1b3f90..53f86fcc06e2c1345d4f7aec56eed31141865406 100644
--- a/content/common/gpu/null_transport_surface.h
+++ b/content/common/gpu/null_transport_surface.h
@@ -21,16 +21,16 @@ class NullTransportSurface : public PassThroughImageTransportSurface {
                        const gfx::GLSurfaceHandle& handle);
 
   // gfx::GLSurfaceAdapter implementation.
-  virtual bool Initialize() override;
-  virtual void Destroy() override;
-  virtual bool SwapBuffers() override;
-  virtual bool PostSubBuffer(int x, int y, int width, int height) override;
-  virtual bool OnMakeCurrent(gfx::GLContext* context) override;
+  bool Initialize() override;
+  void Destroy() override;
+  bool SwapBuffers() override;
+  bool PostSubBuffer(int x, int y, int width, int height) override;
+  bool OnMakeCurrent(gfx::GLContext* context) override;
 
  protected:
-  virtual ~NullTransportSurface();
+  ~NullTransportSurface() override;
 
-  virtual void SendVSyncUpdateIfAvailable() override;
+  void SendVSyncUpdateIfAvailable() override;
 
  private:
   uint32 parent_client_id_;