Standardize usage of virtual/override/final in mojo/

mojo/services/public/cpp/view_manager/lib/view_manager_client_impl.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 "mojo/services/public/cpp/view_manager/lib/view_manager_client_impl.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/stl_util.h"
 #include "mojo/public/cpp/application/application_impl.h"
@@ skipping 54 matching lines @@
     last_view = view;
   }
   return root;
 }
 
 // Responsible for removing a root from the ViewManager when that view is
 // destroyed.
 class RootObserver : public ViewObserver {
  public:
   explicit RootObserver(View* root) : root_(root) {}
-  virtual ~RootObserver() {}
+  ~RootObserver() override {}
 
  private:
   // Overridden from ViewObserver:
-  virtual void OnViewDestroyed(View* view) override {
+  void OnViewDestroyed(View* view) override {
     DCHECK_EQ(view, root_);
     static_cast<ViewManagerClientImpl*>(
         ViewPrivate(root_).view_manager())->RemoveRoot(root_);
     view->RemoveObserver(this);
     delete this;
   }
 
   View* root_;
 
   DISALLOW_COPY_AND_ASSIGN(RootObserver);
@@ skipping 288 matching lines @@
                     base::Unretained(this));
 }
 
 base::Callback<void(ErrorCode)>
     ViewManagerClientImpl::ActionCompletedCallbackWithErrorCode() {
   return base::Bind(&ViewManagerClientImpl::OnActionCompletedWithErrorCode,
                     base::Unretained(this));
 }
 
 }  // namespace mojo