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

chrome/browser/download/download_browsertest.cc

 // 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.
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file.h"
@@ skipping 3409 matching lines @@
     : public content::DownloadTestObserver {
  public:
   explicit DisableSafeBrowsingOnInProgressDownload(Browser* browser)
       : DownloadTestObserver(DownloadManagerForBrowser(browser),
                              1,
                              ON_DANGEROUS_DOWNLOAD_QUIT),
         browser_(browser),
         final_state_seen_(false) {
     Init();
   }
-  virtual ~DisableSafeBrowsingOnInProgressDownload() {}
+  ~DisableSafeBrowsingOnInProgressDownload() override {}
 
-  virtual bool IsDownloadInFinalState(DownloadItem* download) override {
+  bool IsDownloadInFinalState(DownloadItem* download) override {
     if (download->GetState() != DownloadItem::IN_PROGRESS ||
         download->GetTargetFilePath().empty())
       return false;
 
     if (final_state_seen_)
       return true;
 
     final_state_seen_ = true;
     browser_->profile()->GetPrefs()->SetBoolean(prefs::kSafeBrowsingEnabled,
                                                 false);
@@ skipping 142 matching lines @@
       *(downloads[0])));
 
   // Begin feedback and check that the file is "stolen".
   download_protection_service->feedback_service()->BeginFeedbackForDownload(
       downloads[0]);
   std::vector<DownloadItem*> updated_downloads;
   GetDownloads(browser(), &updated_downloads);
   ASSERT_TRUE(updated_downloads.empty());
 }
 #endif