Mixing audio with different latency requirements

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 14 matching lines @@
 
 namespace content {
 
 // A factory for creating AudioRendererSinks and AudioCapturerSources. There is
 // a global factory function that can be installed for the purposes of testing
 // to provide specialized implementations.
 // TODO(olka): rename it, probably split it into AudioRendererSinkFactory and
 // AudioCapturerSourceFactory.
 class CONTENT_EXPORT AudioDeviceFactory {
  public:
-  // Types of audio sources.
+  // Types of audio sources. Each source can have individual mixing and/or
+  // latency requirements for output. The source is specified by the client when
+  // requesting output sink from the factory, and the factory creates the output
+  // sink basing on those requirements.
   enum SourceType {
     kSourceNone = 0,
     kSourceMediaElement,
     kSourceWebRtc,
     kSourceNonRtcAudioTrack,
-    kSourceWebAudio,
-    kSourceLast = kSourceWebAudio  // Only used for validation of format.
+    kSourceWebAudioInteractive,
+    kSourceWebAudioBalanced,
+    kSourceWebAudioPlayback,
+    kSourceWebAudioExact,
+    kSourceLast = kSourceWebAudioExact  // Only used for validation of format.
   };
 
   // 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.
@@ skipping 82 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_