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

chrome/browser/android/dom_distiller/feedback_reporter_android.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_DOM_DISTILLER_FEEDBACK_REPORTER_ANDROID_H_
 #define CHROME_BROWSER_ANDROID_DOM_DISTILLER_FEEDBACK_REPORTER_ANDROID_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 struct FrameNavigateParams;
 struct LoadCommittedDetails;
 }  // namespace content
 
 namespace dom_distiller {
 
 namespace android {
 
 class FeedbackReporterAndroid : content::WebContentsObserver {
  public:
   FeedbackReporterAndroid(JNIEnv* env, jobject obj);
-  virtual ~FeedbackReporterAndroid();
+  ~FeedbackReporterAndroid() override;
 
   // Destroys the FeedbackReporterAndroid.
   void Destroy(JNIEnv* env, jobject obj);
 
   // Observes a new WebContents, if necessary.
   void ReplaceWebContents(JNIEnv* env, jobject obj, jobject jweb_contents);
 
   // WebContentsObserver implementation:
-  virtual void DidNavigateMainFrame(
+  void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) override;
 
  private:
   // FeedbackReporterAndroid on the Java side.
   JavaObjectWeakGlobalRef weak_java_feedback_reporter_;
 
   DISALLOW_COPY_AND_ASSIGN(FeedbackReporterAndroid);
 };
 
 // Registers the FeedbackReporter's native methods through JNI.
 bool RegisterFeedbackReporter(JNIEnv* env);
 
 }  // namespace android
 
 }  // namespace dom_distiller
 
 #endif  // CHROME_BROWSER_ANDROID_DOM_DISTILLER_FEEDBACK_REPORTER_ANDROID_H_