Added the API to create an RTCRtpSender to the Objective C wrapper.

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

Index: webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpSender.h
diff --git a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpSender.h b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpSender.h
index c874b77e6bb0a508186ae94cb7c00cce1e285f2c..f5eb07a7bfdef86d9eacf56b710f0f9f74c1079c 100644
--- a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpSender.h
+++ b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpSender.h
@@ -19,22 +19,20 @@ NS_ASSUME_NONNULL_BEGIN
 RTC_EXPORT
 @protocol RTCRtpSender <NSObject>
 
+/** A unique identifier for this sender. */
+@property(nonatomic, readonly) NSString *senderId;
+
 /** The currently active RTCRtpParameters, as defined in
  *  https://www.w3.org/TR/webrtc/#idl-def-RTCRtpParameters.
  */
-@property(nonatomic, readonly) RTCRtpParameters *parameters;
+@property(nonatomic) RTCRtpParameters *parameters;

[tkchin_webrtc, 2016/04/27 20:22:20]

nit: nonatomic, copy? 

[skvlad, 2016/04/27 23:00:58]

Good catch, copy is the right thing here.

 
 /** The RTCMediaStreamTrack associated with the sender.
  *  Note: reading this property returns a new instance of
  *  RTCMediaStreamTrack. Use isEqual: instead of == to compare
  *  RTCMediaStreamTrack instances.
  */
-@property(nonatomic, readonly) RTCMediaStreamTrack *track;
-
-/** Set the new RTCRtpParameters to be used by the sender.
- *  Returns YES if the new parameters were applied, NO otherwise.
- */
-- (BOOL)setParameters:(RTCRtpParameters *)parameters;
+@property(nonatomic) RTCMediaStreamTrack *track;

[tkchin_webrtc, 2016/04/27 20:22:20]

I'm surprised this wasn't throwing a warning - this seems to be nullable since
the impl returns nil sometimes.

nonatomic, copy, nullable

[skvlad, 2016/04/27 23:00:58]

Is "copy" the right annotation for the behavior we do here, where we're pulling
the native pointer out of the ObjC object and only storing that? Writing and
reading the property effectively produces a copy of the RTCMediaStreamTrack, so
I guess "copy" is reasonable...

[tkchin_webrtc, 2016/04/27 23:13:43]

Sort-of. Since we are overriding the setter these attributes are relatively
meaningless and only serve as a hint to the caller that we are not taking a ref
onto their object.

 
 @end