Pass around the candidate removals events in IOS clients

webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m

Index: webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
diff --git a/webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m b/webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
index f20c490682a3410e8894ae07b8f6ef263faf8f00..2a77cc3f372c4a8593087c771a0f3adc681b00cf 100644
--- a/webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
+++ b/webrtc/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
@@ -49,4 +49,13 @@ static NSString const *kRTCICECandidateSdpKey = @"candidate";
   return data;
 }
 
+- (NSDictionary *)JSONDictionary{
+  NSDictionary *json = @{
+    kRTCICECandidateMLineIndexKey : @(self.sdpMLineIndex),

[tkchin_webrtc, 2016/05/17 02:01:43]

the reason why I didn't like JSONDictionary is because this dictionary is not
the same as the dictionary in JSONData. Maybe the better thing is to have
JSONData call JSONDictionary and then add the type key somewhere else.

but otherwise agree we don't want dup-strings

[honghaiz3, 2016/05/17 06:11:24]

Done. Passed in the type key as an argument. 

+    kRTCICECandidateMidKey : self.sdpMid,
+    kRTCICECandidateSdpKey : self.sdp
+  };
+  return json;
+}
+
 @end