Pass around the candidate removals events in IOS clients

webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.h

 /*
  *  Copyright 2014 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>
 
 #import "WebRTC/RTCIceCandidate.h"
 #import "WebRTC/RTCSessionDescription.h"
 
 typedef enum {
   kARDSignalingMessageTypeCandidate,
+  kARDSignalingMessageTypeCandidateRemoval,
   kARDSignalingMessageTypeOffer,
   kARDSignalingMessageTypeAnswer,
   kARDSignalingMessageTypeBye,
 } ARDSignalingMessageType;
 
 @interface ARDSignalingMessage : NSObject
 
 @property(nonatomic, readonly) ARDSignalingMessageType type;
 
 + (ARDSignalingMessage *)messageFromJSONString:(NSString *)jsonString;
 - (NSData *)JSONData;
 
 @end
 
 @interface ARDICECandidateMessage : ARDSignalingMessage
 
 @property(nonatomic, readonly) RTCIceCandidate *candidate;
 
 - (instancetype)initWithCandidate:(RTCIceCandidate *)candidate;
 
 @end
 
+@interface ARDICECandidateRemovalMessage : ARDSignalingMessage
+
+@property(nonatomic, readonly) NSArray<RTCIceCandidate *> *candidates;
+
+- (instancetype)initWithRemovedCandidates:
+    (NSArray<RTCIceCandidate *> *)candidates;
+
+@end
+
 @interface ARDSessionDescriptionMessage : ARDSignalingMessage
 
 @property(nonatomic, readonly) RTCSessionDescription *sessionDescription;
 
 - (instancetype)initWithDescription:(RTCSessionDescription *)description;
 
 @end
 
 @interface ARDByeMessage : ARDSignalingMessage
 @end