Standardize usage of virtual/override/final in ui/

ui/compositor/test/test_compositor_host_mac.mm

 // 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.
 
 #include "ui/compositor/test/test_compositor_host.h"
 
 #import <AppKit/NSApplication.h>
 #import <AppKit/NSOpenGL.h>
 #import <AppKit/NSView.h>
 #import <AppKit/NSWindow.h>
@@ skipping 53 matching lines @@
 };
 
 // Tests that use the AppKit framework need to have the NSApplication
 // initialized prior to doing anything with display objects such as windows,
 // views, or controls.
 class AppKitHost : public FoundationHost {
  protected:
   AppKitHost() {
     [NSApplication sharedApplication];
   }
-  virtual ~AppKitHost() {
-  }
+  ~AppKitHost() override {}
  private:
   DISALLOW_COPY_AND_ASSIGN(AppKitHost);
 };
 
 // TestCompositorHostMac provides a window surface and a coordinated compositor
 // for use in the compositor unit tests.
 class TestCompositorHostMac : public TestCompositorHost,
                               public AppKitHost {
  public:
   TestCompositorHostMac(const gfx::Rect& bounds,
                         ui::ContextFactory* context_factory);
-  virtual ~TestCompositorHostMac();
+  ~TestCompositorHostMac() override;
 
  private:
   // TestCompositorHost:
-  virtual void Show() override;
-  virtual ui::Compositor* GetCompositor() override;
+  void Show() override;
+  ui::Compositor* GetCompositor() override;
 
   gfx::Rect bounds_;
 
   ui::ContextFactory* context_factory_;
 
   scoped_ptr<ui::Compositor> compositor_;
 
   // Owned.  Released when window is closed.
   NSWindow* window_;
 
@@ skipping 42 matching lines @@
 }
 
 // static
 TestCompositorHost* TestCompositorHost::Create(
     const gfx::Rect& bounds,
     ui::ContextFactory* context_factory) {
   return new TestCompositorHostMac(bounds, context_factory);
 }
 
 }  // namespace ui