Standardize usage of virtual/override/final specifiers.

media/base/audio_hash_unittest.cc

 // Copyright 2013 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/logging.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_hash.h"
 #include "media/base/fake_audio_render_callback.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 20 matching lines @@
     wrapped_bus->set_frames(audio_bus->frames());
 
     // Since FakeAudioRenderCallback generates only a single channel of unique
     // audio data, we need to fill each channel manually.
     for (int ch = 0; ch < audio_bus->channels(); ++ch) {
       wrapped_bus->SetChannelData(0, audio_bus->channel(ch));
       fake_callback_.Render(wrapped_bus.get(), 0);
     }
   }
 
-  virtual ~AudioHashTest() {}
+  ~AudioHashTest() override {}
 
  protected:
   scoped_ptr<AudioBus> bus_one_;
   scoped_ptr<AudioBus> bus_two_;
   FakeAudioRenderCallback fake_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioHashTest);
 };
 
 // Ensure the same data hashes the same.
@@ skipping 106 matching lines @@
   // Twiddle the values too much...
   for (int i = 0; i < bus_one_->frames(); ++i)
     channel[i] += 0.0001f;
 
   AudioHash hash_three;
   hash_three.Update(bus_one_.get(), bus_one_->frames());
   EXPECT_NE(hash_one.ToString(), hash_three.ToString());
 }
 
 }  // namespace media