Allow an external audio processing module to be used in WebRTC

webrtc/voice_engine/include/voe_base.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 106 matching lines @@
   // Removes and disables the observer class for runtime error control
   // and warning notifications. Returns 0.
   virtual int DeRegisterVoiceEngineObserver() = 0;
 
   // Initializes all common parts of the VoiceEngine; e.g. all
   // encoders/decoders, the sound card and core receiving components.
   // This method also makes it possible to install some user-defined external
   // modules:
   // - The Audio Device Module (ADM) which implements all the audio layer
   // functionality in a separate (reference counted) module.
-  // - The AudioProcessing module handles capture-side processing. VoiceEngine
-  // takes ownership of this object.
+  // - The AudioProcessing module handles capture-side processing.
   // - An AudioDecoderFactory - used to create audio decoders.
-  // If NULL is passed for any of these, VoiceEngine will create its own.
-  // Returns -1 in case of an error, 0 otherwise.
+  // If NULL is passed for either of ADM or AudioDecoderFactory, VoiceEngine
+  // will create its own. Returns -1 in case of an error, 0 otherwise.
   // TODO(ajm): Remove default NULLs.
   virtual int Init(AudioDeviceModule* external_adm = NULL,
-                   AudioProcessing* audioproc = NULL,
+                   AudioProcessing* external_apm = nullptr,
                    const rtc::scoped_refptr<AudioDecoderFactory>&
                        decoder_factory = nullptr) = 0;
 
   // Returns NULL before Init() is called.

[Taylor Brandstetter, 2017/06/28 07:19:38]

nit: We generally use "null" in comments, reserving "nullptr"/"NULL" for code

[peah-webrtc, 2017/06/29 11:46:31]

Done.

+  // TODO(peah): Remove this when upstream dependencies have properly been

[Taylor Brandstetter, 2017/06/28 07:19:38]

nit: upstream vs downstream question here too

[peah-webrtc, 2017/06/29 11:46:31]

Done.

+  // resolved.
   virtual AudioProcessing* audio_processing() = 0;
 
   // This method is WIP - DO NOT USE!
   // Returns NULL before Init() is called.
   virtual AudioDeviceModule* audio_device_module() = 0;
 
   // This method is WIP - DO NOT USE!
   // Returns NULL before Init() is called.
   virtual voe::TransmitMixer* transmit_mixer() = 0;
 
@@ skipping 53 matching lines @@
   virtual int AssociateSendChannel(int channel, int accociate_send_channel) = 0;
 
  protected:
   VoEBase() {}
   virtual ~VoEBase() {}
 };
 
 }  // namespace webrtc
 
 #endif  //  WEBRTC_VOICE_ENGINE_VOE_BASE_H