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

webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm

 /*
  *  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
  *  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 "RTCRtpSender+Private.h"
 
+#import "NSString+StdString.h"
 #import "RTCMediaStreamTrack+Private.h"
 #import "RTCRtpParameters+Private.h"
+#import "WebRTC/RTCLogging.h"
 
 #include "webrtc/api/mediastreaminterface.h"
 
 @implementation RTCRtpSender {
   rtc::scoped_refptr<webrtc::RtpSenderInterface> _nativeRtpSender;
 }
 
 - (instancetype)initWithNativeRtpSender:
     (rtc::scoped_refptr<webrtc::RtpSenderInterface>)nativeRtpSender {
   if (self = [super init]) {
     _nativeRtpSender = nativeRtpSender;
   }
   return self;
 }
 
+- (NSString *)senderId {
+  return [NSString stringForStdString:_nativeRtpSender->id()];
+}
+
 - (RTCRtpParameters *)parameters {
   return [[RTCRtpParameters alloc]
       initWithNativeParameters:_nativeRtpSender->GetParameters()];
 }
 
-- (BOOL)setParameters:(RTCRtpParameters *)parameters {
-  return _nativeRtpSender->SetParameters(parameters.nativeParameters);
+- (void)setParameters:(RTCRtpParameters *)parameters {
+  if (!_nativeRtpSender->SetParameters(parameters.nativeParameters)) {
+    RTCLogError(@"Failed to set parameters %@ for %@", parameters, self);

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

maybe what we want here is the pointer?
e.g RTCRtpSender(%p): Failed to set parameters: %@, self, parameters

and if we want to track it down we can print info in init
e.g. RTCRtpSender(%p): Created sender with id: %s, self, _nativeRtpSender->id()

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

I've made it print the pointer here, and the description in the constructor. Is
reading a property in a constructor acceptable for something like the
description?

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

Yes, after self is available it's safe to access property usually.

+  }
 }
 
 - (RTCMediaStreamTrack *)track {
   rtc::scoped_refptr<webrtc::MediaStreamTrackInterface> nativeTrack(
     _nativeRtpSender->track());
   if (nativeTrack) {
     return [[RTCMediaStreamTrack alloc] initWithNativeTrack:nativeTrack];
   }
   return nil;
 }
 
+- (void)setTrack:(RTCMediaStreamTrack *)track {
+  if (!_nativeRtpSender->SetTrack(track.nativeTrack)) {
+    RTCLogError(@"Failed to set track %@ for %@", track, self);
+  }
+}
+
+- (NSString *)description {
+  return [NSString stringWithFormat:@"RTCRtpSender:%@", self.senderId];

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

nit: I've been trying to make our descriptions look like:

RTCRtpSender {
  senderId: <senderId>
}

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

All the descriptions I've found are formatted like this (no field names):
RTCRtpSender {
<senderId>
}

I've made it follow the format you mentioned above, though - if that's the
eventual plan, it's probably better to start doing it the right way.

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

Acknowledged.

+}
+
 @end