Standardize usage of virtual/override/final in content/browser/

content/browser/tracing/tracing_ui.h

 // Copyright (c) 2011 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 CONTENT_BROWSER_TRACING_UI_H_
 #define CONTENT_BROWSER_TRACING_UI_H_
 
 #include <map>
 #include <string>
 
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_ui_controller.h"
 
 namespace content {
 
 // The C++ back-end for the chrome://tracing webui page.
 class CONTENT_EXPORT TracingUI : public WebUIController {
  public:
   explicit TracingUI(WebUI* web_ui);
-  virtual ~TracingUI();
+  ~TracingUI() override;
   void OnMonitoringStateChanged(bool is_monitoring);
   void DoUpload(const base::ListValue* args);
   void OnTraceUploadProgress(int64 current, int64 total);
   void OnTraceUploadComplete(bool success,
                              const std::string& report_id,
                              const std::string& error_message);
 
  private:
   base::WeakPtrFactory<TracingUI> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TracingUI);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_UI_H_