Add implementation and tests for RTCIceServer

webrtc/api/objc/RTCIceServer+Private.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 "RTCIceServer.h"
+
+#include "talk/app/webrtc/peerconnectioninterface.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RTCIceServer ()
+
+/**
+ * IceServer struct representation of this RTCIceServer object's data.
+ * This is needed to pass to the underlying C++ APIs.
+ */
+@property(nonatomic, readonly)
+    webrtc::PeerConnectionInterface::IceServer iceServer;
+
+@end
+
+NS_ASSUME_NONNULL_END