Minor ObjC header updates.

webrtc/api/objc/RTCDataChannelConfiguration.h

Index: webrtc/api/objc/RTCDataChannelConfiguration.h
diff --git a/webrtc/api/objc/RTCDataChannelConfiguration.h b/webrtc/api/objc/RTCDataChannelConfiguration.h
index ef0562ed0ad0a01881145c39b1bc4b5f7eec429d..fbe342d2c86dcce4d851d1155204e217a43f4657 100644
--- a/webrtc/api/objc/RTCDataChannelConfiguration.h
+++ b/webrtc/api/objc/RTCDataChannelConfiguration.h
@@ -8,6 +8,7 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#import <AvailabilityMacros.h>
 #import <Foundation/Foundation.h>
 
 NS_ASSUME_NONNULL_BEGIN
@@ -17,6 +18,9 @@ NS_ASSUME_NONNULL_BEGIN
 /** Set to YES if ordered delivery is required. */
 @property(nonatomic, assign) BOOL isOrdered;
 
+/** Deprecated. Use maxPacketLifeTime. */
+@property(nonatomic, assign) NSInteger maxRetransmitTimeMs DEPRECATED_ATTRIBUTE;
+
 /**
  * Max period in milliseconds in which retransmissions will be sent. After this
  * time, no more retransmissions will be sent. -1 if unset.
@@ -31,8 +35,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, assign) BOOL isNegotiated;
 
-/** The stream id, or SID, for SCTP data channels. -1 if unset. */
-@property(nonatomic, assign) int streamId;
+/** Deprecated. Use channelId. */
+@property(nonatomic, assign) int streamId DEPRECATED_ATTRIBUTE;
+
+/** The id of the data channel. */
+@property(nonatomic, assign) int channelId;
 
 /** Set by the application and opaque to the WebRTC implementation. */
 @property(nonatomic) NSString *protocol;