Update API for Objective-C RTCPeerConnection.

webrtc/api/objc/RTCIceCandidate.mm

 /*
  *  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.
  */
 
@@ skipping 24 matching lines @@
 - (NSString *)description {
   return [NSString stringWithFormat:@"RTCIceCandidate:\n%@\n%ld\n%@",
                                     _sdpMid,
                                     (long)_sdpMLineIndex,
                                     _sdp];
 }
 
 #pragma mark - Private
 
 - (instancetype)initWithNativeCandidate:
-    (webrtc::IceCandidateInterface *)candidate {
+    (const webrtc::IceCandidateInterface *)candidate {
   NSParameterAssert(candidate);
   std::string sdp;
   candidate->ToString(&sdp);
 
   return [self initWithSdp:[NSString stringForStdString:sdp]
              sdpMLineIndex:candidate->sdp_mline_index()
                     sdpMid:[NSString stringForStdString:candidate->sdp_mid()]];
 }
 
 - (rtc::scoped_ptr<webrtc::IceCandidateInterface>)nativeCandidate {
   webrtc::SdpParseError error;
 
   webrtc::IceCandidateInterface *candidate = webrtc::CreateIceCandidate(
       _sdpMid.stdString, _sdpMLineIndex, _sdp.stdString, &error);
 
   if (!candidate) {
     RTCLog(@"Failed to create ICE candidate: %s\nline: %s",
            error.description.c_str(),
            error.line.c_str());
   }
 
   return rtc::scoped_ptr<webrtc::IceCandidateInterface>(candidate);
 }
 
 @end