Tweaks for new Objective-C API.

BUG=

Review URL: https://codereview.webrtc.org/1696673003

Cr-Commit-Position: refs/heads/master@{#11872}
diff --git a/webrtc/api/objc/RTCIceServer+Private.h b/webrtc/api/objc/RTCIceServer+Private.h
index 556936d..8098bee 100644
--- a/webrtc/api/objc/RTCIceServer+Private.h
+++ b/webrtc/api/objc/RTCIceServer+Private.h
@@ -21,7 +21,7 @@
  * This is needed to pass to the underlying C++ APIs.
  */
 @property(nonatomic, readonly)
-    webrtc::PeerConnectionInterface::IceServer iceServer;
+    webrtc::PeerConnectionInterface::IceServer nativeServer;
 
 /** Initialize an RTCIceServer from a native IceServer. */
 - (instancetype)initWithNativeServer: