Standardize usage of virtual/override/final in remoting/

remoting/host/disconnect_window_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.
 
 #import <Cocoa/Cocoa.h>
 
 #import "remoting/host/disconnect_window_mac.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 11 matching lines @@
 - (void)Hide;
 @end
 
 const int kMaximumConnectedNameWidthInPixels = 600;
 
 namespace remoting {
 
 class DisconnectWindowMac : public HostWindow {
  public:
   DisconnectWindowMac();
-  virtual ~DisconnectWindowMac();
+  ~DisconnectWindowMac() override;
 
   // HostWindow overrides.
-  virtual void Start(
-      const base::WeakPtr<ClientSessionControl>& client_session_control)
+  void Start(const base::WeakPtr<ClientSessionControl>& client_session_control)
       override;
 
  private:
   DisconnectWindowController* window_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(DisconnectWindowMac);
 };
 
 DisconnectWindowMac::DisconnectWindowMac()
     : window_controller_(nil) {
@@ skipping 237 matching lines @@
   path = [NSBezierPath bezierPath];
   [path moveToPoint:top];
   [path lineToPoint:bottom];
   [light setStroke];
   [path stroke];
 
   [context setShouldAntialias:alias];
 }
 
 @end