The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ef762c904b723cb488bad237300a5976c29327d3

commit ef762c904b723cb488bad237300a5976c29327d3
Author: olka <olka@chromium.org>
Date: Mon Feb 06 16:45:16 2017

Switch Speech Recognition to asynchronous callback-based AudioManager interactions.

1) This introduces AudioSystem, which provides an asynchronous interface to AudioManager and eventually will replace AudioManager.
The plan is to gradually populate it with all the required methods and switch all AudioManager clients to it,
in preparation for moving AudioManager functionality to Mojo audio service.

2) SpeechRecognizerImpl now uses this interface, which required adding an extra state to its FSM.

3) SpeechRecognizerImpl unit tests are updated to take into account the new threading model and the new state.

BUG= 687981 , 672468 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2675713002
Cr-Commit-Position: refs/heads/master@{#448273}

[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/browser_main_loop.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/browser_main_loop.h
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognition_browsertest.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognition_manager_impl.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognition_manager_impl.h
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognizer_impl.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognizer_impl.h
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/content/browser/speech/speech_recognizer_impl_unittest.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/BUILD.gn
[add] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/audio_system.h
[add] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/audio_system_impl.cc
[add] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/audio_system_impl.h
[add] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/audio_system_impl_unittest.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/mock_audio_manager.cc
[modify] https://crrev.com/ef762c904b723cb488bad237300a5976c29327d3/media/audio/mock_audio_manager.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0bf2c9cdf5dc8bbf2acaac5a5ae4df03c5eaefeb

commit 0bf2c9cdf5dc8bbf2acaac5a5ae4df03c5eaefeb
Author: olka <olka@chromium.org>
Date: Fri Feb 10 11:56:24 2017

SpeechRecognizerImplTest flakiness fix.

SpeechRecognizerImpl::StartRecognition() is asynchronous, so we must
run loop after calling it to make sure it has executed and has posted device info
request to the audio thread before we begin to wait for the audio thread reply.

BUG= 690555 , 687981 

Review-Url: https://codereview.chromium.org/2690463003
Cr-Commit-Position: refs/heads/master@{#449591}

[modify] https://crrev.com/0bf2c9cdf5dc8bbf2acaac5a5ae4df03c5eaefeb/content/browser/speech/speech_recognizer_impl_unittest.cc