AudioManagerBase: Create and run the audio thread lazily.

media/audio/alsa/alsa_output_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 <stdint.h>
 
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 #include "media/audio/alsa/alsa_output.h"
 #include "media/audio/alsa/alsa_wrapper.h"
@@ skipping 77 matching lines @@
   // of active output streams. It is because the number of active streams
   // is managed inside MakeAudioOutputStream, and we don't use
   // MakeAudioOutputStream to create the stream in the tests.
   void ReleaseOutputStream(AudioOutputStream* stream) override {
     DCHECK(stream);
     delete stream;
   }
 
   // We don't mock this method since all tests will do the same thing
   // and use the current task runner.
-  scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() const override {
+  scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() override {
     return base::MessageLoop::current()->task_runner();
   }
 
  private:
   FakeAudioLogFactory fake_audio_log_factory_;
 };
 
 class AlsaPcmOutputStreamTest : public testing::Test {
  protected:
   AlsaPcmOutputStreamTest() {
@@ skipping 744 matching lines @@
 
   // TODO(ajwong): Find a way to test whether or not another task has been
   // posted so we can verify that the Alsa code will indeed break the task
   // posting loop.
 
   test_stream->TransitionTo(AlsaPcmOutputStream::kIsClosed);
   test_stream->Close();
 }
 
 }  // namespace media