iOS: Add ability to specify audio constraints.

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCPeerConnectionFactory.h

 /*
  *  Copyright 2015 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.
  */
 
 #import <Foundation/Foundation.h>
 
 #import <WebRTC/RTCMacros.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
 @class RTCAVFoundationVideoSource;
+@class RTCAudioSource;
 @class RTCAudioTrack;
 @class RTCConfiguration;
 @class RTCMediaConstraints;
 @class RTCMediaStream;
 @class RTCPeerConnection;
 @class RTCVideoSource;
 @class RTCVideoTrack;
 @protocol RTCPeerConnectionDelegate;
 
 RTC_EXPORT
 @interface RTCPeerConnectionFactory : NSObject
 
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 
+/** Initialize an RTCAudioSource with constraints. */
+- (RTCAudioSource *)audioSourceWithConstraints:(nullable RTCMediaConstraints *)constraints;
+
+/** Initialize an RTCAudioTrack with an id. Convenience ctor to use an audio source with no
+ *  constraints.
+ */
+- (RTCAudioTrack *)audioTrackWithTrackId:(NSString *)trackId;
+
+/** Initialize an RTCAudioTrack with a source and an id. */
+- (RTCAudioTrack *)audioTrackWithSource:(RTCAudioSource *)source
+                                trackId:(NSString *)trackId;
+
 /** Initialize an RTCAVFoundationVideoSource with constraints. */
 - (RTCAVFoundationVideoSource *)avFoundationVideoSourceWithConstraints:
     (nullable RTCMediaConstraints *)constraints;
 
-/** Initialize an RTCAudioTrack with an id. */
-- (RTCAudioTrack *)audioTrackWithTrackId:(NSString *)trackId;
-
 /** Initialize an RTCVideoTrack with a source and an id. */
 - (RTCVideoTrack *)videoTrackWithSource:(RTCVideoSource *)source
                                 trackId:(NSString *)trackId;
 
 /** Initialize an RTCMediaStream with an id. */
 - (RTCMediaStream *)mediaStreamWithStreamId:(NSString *)streamId;
 
 /** Initialize an RTCPeerConnection with a configuration, constraints, and
  *  delegate.
  */
@@ skipping 10 matching lines @@
     This API call will likely change in the future */
 - (BOOL)startAecDumpWithFileDescriptor:(int)fileDescriptor
                     maxFileSizeInBytes:(int)maxFileSizeInBytes;
 
 /* Stop an active aecdump recording */
 - (void)stopAecDump;
 
 @end
 
 NS_ASSUME_NONNULL_END