Turn ThreadPriority enum into an enum class.

media/audio/audio_device_thread.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 "media/audio/audio_device_thread.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 97 matching lines @@
   DCHECK(thread_.is_null());
 }
 
 void AudioDeviceThread::Thread::Start() {
   base::AutoLock auto_lock(callback_lock_);
   DCHECK(thread_.is_null());
   // This reference will be released when the thread exists.
   AddRef();
 
   PlatformThread::CreateWithPriority(0, this, &thread_,
-                                     base::kThreadPriority_RealtimeAudio);
+                                     base::ThreadPriority::REALTIME_AUDIO);
   CHECK(!thread_.is_null());
 }
 
 void AudioDeviceThread::Thread::Stop(base::MessageLoop* loop_for_join) {
   socket_.Shutdown();
 
   base::PlatformThreadHandle thread = base::PlatformThreadHandle();
 
   {  // NOLINT
     base::AutoLock auto_lock(callback_lock_);
@@ skipping 89 matching lines @@
 }
 
 AudioDeviceThread::Callback::~Callback() {}
 
 void AudioDeviceThread::Callback::InitializeOnAudioThread() {
   MapSharedMemory();
   CHECK(shared_memory_.memory());
 }
 
 }  // namespace media.