Expose TurnCustomizer as a native ObjC property.

Bug: webrtc:8471
Change-Id: Ic0d904b0c3742e552f20fbebb26d55d2bdd76c72
Reviewed-on: https://webrtc-review.googlesource.com/16566
Commit-Queue: Zeke Chin <tkchin@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20481}

sdk/objc/Framework/Classes/PeerConnection/RTCConfiguration+Native.h

@@ -0,0 +1,27 @@
+/*
+ *  Copyright 2017 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 "WebRTC/RTCConfiguration.h"
+
+#include "api/peerconnectioninterface.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RTCConfiguration ()
+
+/** Optional TurnCustomizer.
+ *  With this class one can modify outgoing TURN messages.
+ *  The object passed in must remain valid until PeerConnection::Close() is called.
+ */
+@property(nonatomic, nullable) webrtc::TurnCustomizer *turnCustomizer;
+
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/Framework/Classes/PeerConnection/RTCConfiguration.mm

@@ -12,6 +12,7 @@
 
 #include <memory>
 
+#import "RTCConfiguration+Native.h"
 #import "RTCIceServer+Private.h"
 #import "RTCIntervalRange+Private.h"
 #import "WebRTC/RTCLogging.h"
@@ -41,6 +42,7 @@
     _shouldPresumeWritableWhenFullyRelayed;
 @synthesize iceCheckMinInterval = _iceCheckMinInterval;
 @synthesize iceRegatherIntervalRange = _iceRegatherIntervalRange;
+@synthesize turnCustomizer = _turnCustomizer;
 
 - (instancetype)init {
   // Copy defaults.
@@ -92,6 +94,7 @@
       _iceRegatherIntervalRange =
           [[RTCIntervalRange alloc] initWithNativeIntervalRange:nativeIntervalRange];
     }
+    _turnCustomizer = config.turn_customizer;
   }
   return self;
 }
@@ -178,6 +181,9 @@
     nativeConfig->ice_regather_interval_range =
         rtc::Optional<rtc::IntervalRange>(*nativeIntervalRange);
   }
+  if (_turnCustomizer) {
+    nativeConfig->turn_customizer = _turnCustomizer;
+  }
   return nativeConfig.release();
 }