Add implementation and tests for RTCIceServer

webrtc/base/objc/NSString+StdString.h

Index: webrtc/base/objc/NSString+StdString.h
diff --git a/webrtc/examples/objc/AppRTCDemo/ARDTURNClient.h b/webrtc/base/objc/NSString+StdString.h
similarity index 58%
copy from webrtc/examples/objc/AppRTCDemo/ARDTURNClient.h
copy to webrtc/base/objc/NSString+StdString.h
index 8f2a81734229fca65421613794b3ab1accca8c2e..532032b3fca66977290d612f1e998c205cceef00 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDTURNClient.h
+++ b/webrtc/base/objc/NSString+StdString.h
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *  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
@@ -10,11 +10,16 @@
 
 #import <Foundation/Foundation.h>
 
-@protocol ARDTURNClient <NSObject>
+#include <string>
 
-// Returns TURN server urls if successful.
-- (void)requestServersWithCompletionHandler:
-    (void (^)(NSArray *turnServers,
-              NSError *error))completionHandler;
+NS_ASSUME_NONNULL_BEGIN
+
+@interface NSString (StdString)
+
+@property(nonatomic, readonly) std::string stdString;
+
++ (std::string)stdStringForString:(NSString *)nsString;
 
 @end
+
+NS_ASSUME_NONNULL_END