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

ui/aura/window_tree_host_mac.h

 // Copyright 2014 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 UI_AURA_WINDOW_TREE_HOST_MAC_H_
 #define UI_AURA_WINDOW_TREE_HOST_MAC_H_
 
 #include <vector>
 
 #include "base/mac/scoped_nsobject.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace ui {
 class MouseEvent;
 }
 
 namespace aura {
 
 namespace internal {
 class TouchEventCalibrate;
 }
 
 class AURA_EXPORT WindowTreeHostMac : public WindowTreeHost {
  public:
   explicit WindowTreeHostMac(const gfx::Rect& bounds);
-  virtual ~WindowTreeHostMac();
+  ~WindowTreeHostMac() override;
 
  private:
   // WindowTreeHost Overrides.
-  virtual ui::EventSource* GetEventSource() override;
-  virtual gfx::AcceleratedWidget GetAcceleratedWidget() override;
-  virtual void Show() override;
-  virtual void Hide() override;
-  virtual void ToggleFullScreen() override;
-  virtual gfx::Rect GetBounds() const override;
-  virtual void SetBounds(const gfx::Rect& bounds) override;
-  virtual gfx::Insets GetInsets() const override;
-  virtual void SetInsets(const gfx::Insets& insets) override;
-  virtual gfx::Point GetLocationOnNativeScreen() const override;
-  virtual void SetCapture() override;
-  virtual void ReleaseCapture() override;
-  virtual bool ConfineCursorToRootWindow() override;
-  virtual void UnConfineCursor() override;
-  virtual void SetCursorNative(gfx::NativeCursor cursor_type) override;
-  virtual void MoveCursorToNative(const gfx::Point& location) override;
-  virtual void OnCursorVisibilityChangedNative(bool show) override;
-  virtual void OnDeviceScaleFactorChanged(float device_scale_factor) override;
+  ui::EventSource* GetEventSource() override;
+  gfx::AcceleratedWidget GetAcceleratedWidget() override;
+  void Show() override;
+  void Hide() override;
+  void ToggleFullScreen() override;
+  gfx::Rect GetBounds() const override;
+  void SetBounds(const gfx::Rect& bounds) override;
+  gfx::Insets GetInsets() const override;
+  void SetInsets(const gfx::Insets& insets) override;
+  gfx::Point GetLocationOnNativeScreen() const override;
+  void SetCapture() override;
+  void ReleaseCapture() override;
+  bool ConfineCursorToRootWindow() override;
+  void UnConfineCursor() override;
+  void SetCursorNative(gfx::NativeCursor cursor_type) override;
+  void MoveCursorToNative(const gfx::Point& location) override;
+  void OnCursorVisibilityChangedNative(bool show) override;
+  void OnDeviceScaleFactorChanged(float device_scale_factor) override;
 
  private:
   base::scoped_nsobject<NSWindow> window_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMac);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TREE_HOST_MAC_H_