Standardize usage of virtual/override/final in chrome/

chrome/app_shim/chrome_main_app_mode_mac.mm

 // Copyright 2013 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.
 
 // On Mac, one can't make shortcuts with command-line arguments. Instead, we
 // produce small app bundles which locate the Chromium framework and load it,
 // passing the appropriate data. This is the entry point into the framework for
 // those app bundles.
 
 #import <Cocoa/Cocoa.h>
@@ skipping 70 matching lines @@
 // a QuitApp message.
 - (void)terminateNow;
 
 @end
 
 // The AppShimController is responsible for communication with the main Chrome
 // process, and generally controls the lifetime of the app shim process.
 class AppShimController : public IPC::Listener {
  public:
   AppShimController();
-  virtual ~AppShimController();
+  ~AppShimController() override;
 
   // Called when the main Chrome process responds to the Apple Event ping that
   // was sent, or when the ping fails (if |success| is false).
   void OnPingChromeReply(bool success);
 
   // Called |kPingChromeTimeoutSeconds| after startup, to allow a timeout on the
   // ping event to be detected.
   void OnPingChromeTimeout();
 
   // Connects to Chrome and sends a LaunchApp message.
@@ skipping 10 matching lines @@
   void SendQuitApp();
 
   // Called when the app is activated, e.g. by clicking on it in the dock, by
   // dropping a file on the dock icon, or by Cmd+Tabbing to it.
   // Returns whether the message was sent.
   bool SendFocusApp(apps::AppShimFocusType focus_type,
                     const std::vector<base::FilePath>& files);
 
  private:
   // IPC::Listener implemetation.
-  virtual bool OnMessageReceived(const IPC::Message& message) override;
-  virtual void OnChannelError() override;
+  bool OnMessageReceived(const IPC::Message& message) override;
+  void OnChannelError() override;
 
   // If Chrome failed to launch the app, |success| will be false and the app
   // shim process should die.
   void OnLaunchAppDone(apps::AppShimLaunchResult result);
 
   // Hide this app.
   void OnHide();
 
   // Requests user attention.
   void OnRequestUserAttention();
@@ skipping 550 matching lines @@
     // minute.
     main_message_loop.PostTask(
         FROM_HERE,
         base::Bind(&AppShimController::Init,
                    base::Unretained(&controller)));
   }
 
   main_message_loop.Run();
   return 0;
 }