iOS: Add ability to specify audio constraints.

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

Index: webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
diff --git a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioTrack.h b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
similarity index 73%
copy from webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioTrack.h
copy to webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
index a9f5fe22777ef4c954676e557c6b5ad3168ed22c..a86f42bbb75cd1f0d7d62806cac1335c1d62ee09 100644
--- a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioTrack.h
+++ b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
+ *  Copyright 2016 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
@@ -8,13 +8,15 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#import <Foundation/Foundation.h>
+
 #import <WebRTC/RTCMacros.h>
-#import <WebRTC/RTCMediaStreamTrack.h>
+#import <WebRTC/RTCMediaSource.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
 RTC_EXPORT
-@interface RTCAudioTrack : RTCMediaStreamTrack
+@interface RTCAudioSource : RTCMediaSource
 
 - (instancetype)init NS_UNAVAILABLE;