Update API for Objective-C RTCAudioTrack and RTCVideoTrack.

webrtc/api/objc/RTCAudioTrack.mm

+/*
+ *  Copyright 2015 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 "RTCAudioTrack.h"
+
+#import "webrtc/api/objc/RTCAudioTrack+Private.h"
+#import "webrtc/api/objc/RTCMediaStreamTrack+Private.h"
+#import "webrtc/api/objc/RTCPeerConnectionFactory+Private.h"
+#import "webrtc/base/objc/NSString+StdString.h"
+
+@implementation RTCAudioTrack
+
+- (instancetype)initWithFactory:(RTCPeerConnectionFactory *)factory
+                        trackId:(NSString *)trackId {
+  NSParameterAssert(factory);
+  NSParameterAssert(trackId.length);
+  std::string nativeID = [NSString stdStringForString:trackId];
+  rtc::scoped_refptr<webrtc::AudioTrackInterface> track =
+      factory.nativeFactory->CreateAudioTrack(nativeID, nullptr);
+  self =

[tkchin_webrtc, 2016/01/21 01:23:30]

return [self initWIth...] should be enough?

[hjon, 2016/01/21 19:53:27]

Done.

+      [self initWithNativeMediaTrack:track type:RTCMediaStreamTrackTypeAudio];
+  return self;
+}
+
+- (instancetype)initWithNativeMediaTrack:
+    (rtc::scoped_refptr<webrtc::MediaStreamTrackInterface>)nativeMediaTrack
+                                    type:(RTCMediaStreamTrackType)type {
+  NSParameterAssert(nativeMediaTrack);
+  NSParameterAssert(type == RTCMediaStreamTrackTypeAudio);
+  self = [super initWithNativeMediaTrack:nativeMediaTrack

[tkchin_webrtc, 2016/01/21 01:23:30]

This should follow normal super patterns?

if (self = [super initWith...]) {

}
return self

[hjon, 2016/01/21 19:53:27]

I think return self = [super initWith...]; should be sufficient here, since
there isn't any extra work to do?

+                                    type:type];
+  return self;
+}
+
+@end