Removes unused WaveOut APIs from ADM

webrtc/modules/audio_device/include/audio_device.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 90 matching lines @@
   virtual int32_t StopPlayout() = 0;
   virtual bool Playing() const = 0;
   virtual int32_t StartRecording() = 0;
   virtual int32_t StopRecording() = 0;
   virtual bool Recording() const = 0;
 
   // Microphone Automatic Gain Control (AGC)
   virtual int32_t SetAGC(bool enable) = 0;
   virtual bool AGC() const = 0;
 
-  // Volume control based on the Windows Wave API (Windows only)
+  // Deprecated.
+  // TODO(henrika): to be removed.
   virtual int32_t SetWaveOutVolume(uint16_t volumeLeft,

[The Sun (google.com), 2017/08/29 12:56:43]

Is it possible to remove them directly? I can only see there being a problem if
an external impl uses "override".

-                                   uint16_t volumeRight) = 0;
+                                   uint16_t volumeRight) { return -1; }
   virtual int32_t WaveOutVolume(uint16_t* volumeLeft,
-                                uint16_t* volumeRight) const = 0;
+                                uint16_t* volumeRight) const { return -1; }
 
   // Audio mixer initialization
   virtual int32_t InitSpeaker() = 0;
   virtual bool SpeakerIsInitialized() const = 0;
   virtual int32_t InitMicrophone() = 0;
   virtual bool MicrophoneIsInitialized() const = 0;
 
   // Speaker volume controls
   virtual int32_t SpeakerVolumeIsAvailable(bool* available) = 0;
   virtual int32_t SetSpeakerVolume(uint32_t volume) = 0;
@@ skipping 80 matching lines @@
   virtual int GetRecordAudioParameters(AudioParameters* params) const = 0;
 #endif  // WEBRTC_IOS
 
  protected:
   ~AudioDeviceModule() override {}
 };
 
 }  // namespace webrtc
 
 #endif  // MODULES_AUDIO_DEVICE_INCLUDE_AUDIO_DEVICE_H_