Standardize usage of virtual/override/final specifiers.

content/browser/download/drag_download_file_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 "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/ref_counted.h"
 #include "content/browser/download/download_file_factory.h"
 #include "content/browser/download/download_file_impl.h"
 #include "content/browser/download/download_item_impl.h"
@@ skipping 31 matching lines @@
 
  private:
   virtual ~MockDownloadFileObserver() {}
 
   DISALLOW_COPY_AND_ASSIGN(MockDownloadFileObserver);
 };
 
 class DragDownloadFileTest : public ContentBrowserTest {
  public:
   DragDownloadFileTest() {}
-  virtual ~DragDownloadFileTest() {}
+  ~DragDownloadFileTest() override {}
 
   void Succeed() {
     BrowserThread::PostTask(BrowserThread::UI,
                             FROM_HERE,
                             base::MessageLoopForUI::current()->QuitClosure());
   }
 
   void FailFast() {
     CHECK(false);
   }
@@ skipping 66 matching lines @@
       .WillOnce(InvokeWithoutArgs(this, &DragDownloadFileTest::Succeed));
   ON_CALL(*observer.get(), OnDownloadAborted())
       .WillByDefault(InvokeWithoutArgs(this, &DragDownloadFileTest::FailFast));
   file->Start(observer.get());
   RunMessageLoop();
 }
 
 // TODO(benjhayden): Test Stop().
 
 }  // namespace content