Standardize usage of virtual/override/final specifiers.

content/renderer/media/media_stream_video_source_unittest.cc

 // 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.
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ skipping 38 matching lines @@
         gfx::Size(352, 288), 30, media::PIXEL_FORMAT_I420));
     formats.push_back(media::VideoCaptureFormat(
         gfx::Size(320, 240), 30, media::PIXEL_FORMAT_I420));
     mock_source_->SetSupportedFormats(formats);
     webkit_source_.initialize(base::UTF8ToUTF16("dummy_source_id"),
                               blink::WebMediaStreamSource::TypeVideo,
                               base::UTF8ToUTF16("dummy_source_name"));
     webkit_source_.setExtraData(mock_source_);
   }
 
-  virtual void TearDown() {
+  void TearDown() override {
     webkit_source_.reset();
     blink::WebHeap::collectAllGarbageForTesting();
   }
 
  protected:
   // Create a track that's associated with |webkit_source_|.
   blink::WebMediaStreamTrack CreateTrack(
       const std::string& id,
       const blink::WebMediaConstraints& constraints) {
     bool enabled = true;
@@ skipping 717 matching lines @@
   run_loop2.Run();
 
   EXPECT_EQ(muted_state, false);
   EXPECT_EQ(track.source().readyState(),
             blink::WebMediaStreamSource::ReadyStateLive);
 
   MediaStreamVideoSink::RemoveFromVideoTrack(&sink, track);
 }
 
 }  // namespace content