Standardize usage of virtual/override/final in mojo/

mojo/services/native_viewport/platform_viewport_headless.h

Index: mojo/services/native_viewport/platform_viewport_headless.h
diff --git a/mojo/services/native_viewport/platform_viewport_headless.h b/mojo/services/native_viewport/platform_viewport_headless.h
index 9b9743fab0966aa9ea5985cf4702f78538e0af7a..ba2a5b15d6dd7f3763135b1770d2a6b4f516108f 100644
--- a/mojo/services/native_viewport/platform_viewport_headless.h
+++ b/mojo/services/native_viewport/platform_viewport_headless.h
@@ -10,7 +10,7 @@ namespace mojo {
 
 class PlatformViewportHeadless : public PlatformViewport {
  public:
-  virtual ~PlatformViewportHeadless();
+  ~PlatformViewportHeadless() override;
 
   static scoped_ptr<PlatformViewport> Create(Delegate* delegate);
 
@@ -18,14 +18,14 @@ class PlatformViewportHeadless : public PlatformViewport {
   explicit PlatformViewportHeadless(Delegate* delegate);
 
   // Overridden from PlatformViewport:
-  virtual void Init(const gfx::Rect& bounds) override;
-  virtual void Show() override;
-  virtual void Hide() override;
-  virtual void Close() override;
-  virtual gfx::Size GetSize() override;
-  virtual void SetBounds(const gfx::Rect& bounds) override;
-  virtual void SetCapture() override;
-  virtual void ReleaseCapture() override;
+  void Init(const gfx::Rect& bounds) override;
+  void Show() override;
+  void Hide() override;
+  void Close() override;
+  gfx::Size GetSize() override;
+  void SetBounds(const gfx::Rect& bounds) override;
+  void SetCapture() override;
+  void ReleaseCapture() override;
 
   Delegate* delegate_;
   gfx::Rect bounds_;