Reland "Refactor audio manager for Android to avoid heavy tasks at startup"

media/audio/android/audio_manager_android.h

 // 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.
 
 #ifndef MEDIA_AUDIO_ANDROID_AUDIO_MANAGER_ANDROID_H_
 #define MEDIA_AUDIO_ANDROID_AUDIO_MANAGER_ANDROID_H_
 
 #include <set>
 
 #include "base/android/jni_android.h"
@@ skipping 49 matching lines @@
   void SetMute(JNIEnv* env, jobject obj, jboolean muted);
 
  protected:
   virtual ~AudioManagerAndroid();
 
   virtual AudioParameters GetPreferredOutputStreamParameters(
       const std::string& output_device_id,
       const AudioParameters& input_params) OVERRIDE;
 
  private:
+  bool HadNoAudioStreams();
   void Init();
   void Close();
-  void SetAudioMode(int mode);
-  void SetAudioDevice(const std::string& device_id);
+  void SetCommunicationAudioModeOn(bool on);
+  bool SetAudioDevice(const std::string& device_id);
   int GetNativeOutputSampleRate();
   bool IsAudioLowLatencySupported();
   int GetAudioLowLatencyOutputFrameSize();
   int GetOptimalOutputFrameSize(int sample_rate, int channels);
 
   void DoSetMuteOnAudioThread(bool muted);
 
   // Allow the AudioAndroidTest to access private methods.
   FRIEND_TEST_ALL_PREFIXES(AudioAndroidOutputTest, IsAudioLowLatencySupported);
 
   // Java AudioManager instance.
   base::android::ScopedJavaGlobalRef<jobject> j_audio_manager_;
 
   typedef std::set<OpenSLESOutputStream*> OutputStreams;
   OutputStreams streams_;
   // TODO(wjia): remove this lock once unit test modules are fixed to call
   // AudioManager::MakeAudioOutputStream on the audio thread. For now, this
   // lock is used to guard access to |streams_|.
   base::Lock streams_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerAndroid);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_ANDROID_AUDIO_MANAGER_ANDROID_H_