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

content/browser/web_contents/aura/gesture_nav_simple.cc

 // 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.
 
 #include "content/browser/web_contents/aura/gesture_nav_simple.h"
 
 #include "cc/layers/layer.h"
 #include "content/browser/frame_host/navigation_controller_impl.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/web_contents/web_contents_impl.h"
@@ skipping 36 matching lines @@
 // animation.
 template <class T>
 class DeleteAfterAnimation : public ui::ImplicitAnimationObserver {
  public:
   explicit DeleteAfterAnimation(scoped_ptr<T> object)
       : object_(object.Pass()) {}
 
  private:
   friend class base::DeleteHelper<DeleteAfterAnimation<T> >;
 
-  virtual ~DeleteAfterAnimation() {}
+  ~DeleteAfterAnimation() override {}
 
   // ui::ImplicitAnimationObserver:
-  virtual void OnImplicitAnimationsCompleted() override {
+  void OnImplicitAnimationsCompleted() override {
     // Deleting an observer when a ScopedLayerAnimationSettings is iterating
     // over them can cause a crash (which can happen during tests). So instead,
     // schedule this observer to be deleted soon.
     BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, this);
   }
 
   scoped_ptr<T> object_;
   DISALLOW_COPY_AND_ASSIGN(DeleteAfterAnimation);
 };
 
@@ skipping 156 matching lines @@
   clip_layer_->SetBounds(window->layer()->bounds());
   clip_layer_->SetMasksToBounds(true);
   clip_layer_->Add(arrow_.get());
 
   ui::Layer* parent = window->layer()->parent();
   parent->Add(clip_layer_.get());
   parent->StackAtTop(clip_layer_.get());
 }
 
 }  // namespace content