Tweaks for new Objective-C API.

webrtc/api/objc/RTCPeerConnection.h

Index: webrtc/api/objc/RTCPeerConnection.h
diff --git a/webrtc/api/objc/RTCPeerConnection.h b/webrtc/api/objc/RTCPeerConnection.h
index 86668a5b21e3eed968fa3c680bdcce41b53eb5f8..d63683ec12ee4c05e1c93f16bb111fceb67847fa 100644
--- a/webrtc/api/objc/RTCPeerConnection.h
+++ b/webrtc/api/objc/RTCPeerConnection.h
@@ -112,9 +112,9 @@ typedef NS_ENUM(NSInteger, RTCStatsOutputLevel) {
     RTCSessionDescription *localDescription;
 @property(nonatomic, readonly, nullable)
     RTCSessionDescription *remoteDescription;
-@property(nonatomic, readonly) RTCSignalingState signalingState;
-@property(nonatomic, readonly) RTCIceConnectionState iceConnectionState;
-@property(nonatomic, readonly) RTCIceGatheringState iceGatheringState;
+@property(nonatomic, assign, readonly) RTCSignalingState signalingState;

[tkchin_webrtc, 2016/02/26 00:45:25]

ditto no assign + readonly

+@property(nonatomic, assign, readonly) RTCIceConnectionState iceConnectionState;
+@property(nonatomic, assign, readonly) RTCIceGatheringState iceGatheringState;
 
 - (nonnull instancetype)init NS_UNAVAILABLE;
 
@@ -181,7 +181,7 @@ typedef NS_ENUM(NSInteger, RTCStatsOutputLevel) {
  *  statistics are gathered for all tracks.
  */
 - (void)statsForTrack:
-    (nonnull RTCMediaStreamTrack *)mediaStreamTrack
+    (nullable RTCMediaStreamTrack *)mediaStreamTrack
      statsOutputLevel:(RTCStatsOutputLevel)statsOutputLevel
     completionHandler:
     (nullable void (^)(NSArray * _Nonnull stats))completionHandler;