Support a user-provided string for the TLS ALPN extension.

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCIceServer.h

 /*
  *  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.
  */
 
@@ skipping 25 matching lines @@
  */
 @property(nonatomic, readonly) RTCTlsCertPolicy tlsCertPolicy;
 
 /**
   If the URIs in |urls| only contain IP addresses, this field can be used
   to indicate the hostname, which may be necessary for TLS (using the SNI
   extension). If |urls| itself contains the hostname, this isn't necessary.
  */
 @property(nonatomic, readonly, nullable) NSString *hostname;
 
+/** List of protocols to be used in the TLS ALPN extension. */
+@property(nonatomic, readonly) NSArray<NSString *> *tlsAlpnProtocols;
+
 - (nonnull instancetype)init NS_UNAVAILABLE;
 
 /** Convenience initializer for a server with no authentication (e.g. STUN). */
 - (instancetype)initWithURLStrings:(NSArray<NSString *> *)urlStrings;
 
 /**
  * Initialize an RTCIceServer with its associated URLs, optional username,
  * optional credential, and credentialType.
  */
 - (instancetype)initWithURLStrings:(NSArray<NSString *> *)urlStrings
@@ skipping 10 matching lines @@
                      tlsCertPolicy:(RTCTlsCertPolicy)tlsCertPolicy;
 
 /**
  * Initialize an RTCIceServer with its associated URLs, optional username,
  * optional credential, TLS cert policy and hostname.
  */
 - (instancetype)initWithURLStrings:(NSArray<NSString *> *)urlStrings
                           username:(nullable NSString *)username
                         credential:(nullable NSString *)credential
                      tlsCertPolicy:(RTCTlsCertPolicy)tlsCertPolicy
-                          hostname:(nullable NSString *)hostname NS_DESIGNATED_INITIALIZER;
+                          hostname:(nullable NSString *)hostname;
+
+/**
+ * Initialize an RTCIceServer with its associated URLs, optional username,
+ * optional credential, TLS cert policy, hostname and ALPN protocols.
+ */
+- (instancetype)initWithURLStrings:(NSArray<NSString *> *)urlStrings
+                          username:(nullable NSString *)username
+                        credential:(nullable NSString *)credential
+                     tlsCertPolicy:(RTCTlsCertPolicy)tlsCertPolicy
+                          hostname:(nullable NSString *)hostname
+                  tlsAlpnProtocols:(NSArray<NSString *> *)tlsAlpnProtocols
+      NS_DESIGNATED_INITIALIZER;
 
 @end
 
 NS_ASSUME_NONNULL_END