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

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

Index: webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm
diff --git a/webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm b/webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm
index 71030029adf4005792f535e89d679fe20c591c06..86ceea8dfe448100eb61c39827ec3ab76ddb9f27 100644
--- a/webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm
+++ b/webrtc/sdk/objc/Framework/Classes/RTCRtpSender.mm
@@ -10,8 +10,10 @@
 
 #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"
 
@@ -27,13 +29,19 @@
   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 {
@@ -45,4 +53,14 @@
   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