Added support for changing the volume of RTCAudioSource as discussed in BUG=webrtc:6533

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/RTCAudioSource.h b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
index a86f42bbb75cd1f0d7d62806cac1335c1d62ee09..d24cc707709eb72f6f7d4151ceeb75243c26aff7 100644
--- a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
+++ b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCAudioSource.h
@@ -20,6 +20,8 @@ RTC_EXPORT
 
 - (instancetype)init NS_UNAVAILABLE;
 
+@property(nonatomic) double volume;

[tkchin_webrtc, 2016/11/28 21:29:54]

nit: nonatomic, assign

doco that this is temporary, link to a bug with plans for future fix

doco what the valid range is, what happens if out of bounds

[the sun, 2016/11/30 11:38:04]

Currently SetVolume() is a no-op for local streams.

[Frederik, 2016/12/01 18:54:31]

Done.

+
 @end
 
 NS_ASSUME_NONNULL_END