Update API for Objective-C RTCDataChannelConfiguration.

BUG=

Review URL: https://codereview.webrtc.org/1616363005

Cr-Commit-Position: refs/heads/master@{#11405}
diff --git a/webrtc/api/objc/RTCDataChannelConfiguration.h b/webrtc/api/objc/RTCDataChannelConfiguration.h
new file mode 100644
index 0000000..c343eb5
--- /dev/null
+++ b/webrtc/api/objc/RTCDataChannelConfiguration.h
@@ -0,0 +1,42 @@
+/*
+ *  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.
+ */
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RTCDataChannelConfiguration : NSObject
+
+/** Set to YES if ordered delivery is required. */
+@property(nonatomic) BOOL isOrdered;
+
+/**
+ * Max period in milliseconds in which retransmissions will be sent. After this
+ * time, no more retransmissions will be sent. -1 if unset.
+ */
+@property(nonatomic) int maxPacketLifeTime;
+
+/** The max number of retransmissions. -1 if unset. */
+@property(nonatomic) int maxRetransmits;
+
+/** Set to YES if the channel has been externally negotiated and we do not send
+ * an in-band signalling in the form of an "open" message.
+ */
+@property(nonatomic) BOOL isNegotiated;
+
+/** The stream id, or SID, for SCTP data channels. -1 if unset. */
+@property(nonatomic) int streamId;
+
+/** Set by the application and opaque to the WebRTC implementation. */
+@property(nonatomic) NSString *protocol;
+
+@end
+
+NS_ASSUME_NONNULL_END