Update API for Objective-C RTCSessionDescription.

webrtc/api/objc/RTCSessionDescription.h

 /*
  *  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 <Foundation/Foundation.h>
 
-#include <string>
-
 NS_ASSUME_NONNULL_BEGIN
 
-@interface NSString (StdString)
+@interface RTCSessionDescription : NSObject
 
-@property(nonatomic, readonly) std::string stdString;
+/** The type of session description. */
+@property(nonatomic, copy, readonly) NSString *type;

[tkchin_webrtc, 2016/01/05 16:29:18]

copy is technically for setters only. Since we're not changing this to readwrite
in a private interface we can just omit it.

https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Progra...

[hjon, 2016/01/05 22:16:20]

Done.

 
-+ (std::string)stdStringForString:(NSString *)nsString;
-+ (NSString *)stringForStdString:(const std::string&)stdString;
+/** The SDP string representation of this session description. */
+@property(nonatomic, copy, readonly) NSString *sdp;
+
+- (instancetype)init NS_UNAVAILABLE;
+
+/** Initialize a session description with a type and SDP string. */
+- (instancetype)initWithType:(NSString *)type sdp:(NSString *)sdp;
 
 @end
 
 NS_ASSUME_NONNULL_END