Getting rid of AudioHardwareConfig and its synchronous IPC.

content/renderer/media/audio_device_factory.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 CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
 #define CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 30 matching lines @@
     kSourceMediaElement,
     kSourceWebRtc,
     kSourceNonRtcAudioTrack,
     kSourceWebAudioInteractive,
     kSourceWebAudioBalanced,
     kSourceWebAudioPlayback,
     kSourceWebAudioExact,
     kSourceLast = kSourceWebAudioExact  // Only used for validation of format.
   };
 
+  // TODO(olka, guidou): replace with actulal frame id everywhere.

[Guido Urdaneta, 2016/07/06 14:16:16]

fix typo: s/actulal/actual

+  enum { kUnknownFrameIdForDefaultDevice = 1 };

[DaleCurtis, 2016/07/06 18:53:36]

Why do we need this? Should we instead just have a method which doesn't take a
render frame id?

[miu, 2016/07/06 19:10:57]

Not sure if I understand everything going on here, but we should never allow
audio output from a render frame without associating the output stream with the
frame ID. Otherwise, several important browser-level features will break: the
audio indicator, tab OOM-killer management, tab mute, tab capture, etc.

What worries me is that we currently need this "unknown" enum. That infers there
is already broken code creating audio output without specifying its source
render frame.

IIRC, I had a DCHECK in AudioRendererHost to prevent streams with invalid render
frame IDs from being created. Did someone get rid of that?

[o1ka, 2016/07/13 09:52:41]

removed

+
   // Creates a sink for AudioRendererMixer.
   // |render_frame_id| refers to the RenderFrame containing the entity
   // producing the audio. If |session_id| is nonzero, it is used by the browser
   // to select the correct input device ID and its associated output device, if
   // it exists. If |session_id| is zero, |device_id| and |security_origin|
   // identify the output device to use.
   // If |session_id| is zero and |device_id| and |security_origin| are empty,
   // the default output device will be selected.
   static scoped_refptr<media::AudioRendererSink> NewAudioRendererMixerSink(
       int render_frame_id,
@@ skipping 17 matching lines @@
   // Basing on |source_type| and build configuration, audio played out through
   // the sink goes to AOD directly or can be mixed with other audio before that.
   static scoped_refptr<media::SwitchableAudioRendererSink>
   NewSwitchableAudioRendererSink(SourceType source_type,
                                  int render_frame_id,
                                  int session_id,
                                  const std::string& device_id,
                                  const url::Origin& security_origin);
 
   // A helper to get device info in the absence of AudioOutputDevice.
+  // Must be called on renderer thread only.
   static media::OutputDeviceInfo GetOutputDeviceInfo(
       int render_frame_id,
       int session_id,
       const std::string& device_id,
       const url::Origin& security_origin);
 
   // Creates an AudioCapturerSource using the currently registered factory.
   // |render_frame_id| refers to the RenderFrame containing the entity
   // consuming the audio.
   static scoped_refptr<media::AudioCapturerSource> NewAudioCapturerSource(
@@ skipping 43 matching lines @@
       int session_id,
       const std::string& device_id,
       const url::Origin& security_origin);
 
   DISALLOW_COPY_AND_ASSIGN(AudioDeviceFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_