Add flag in ios to support disabling high-cost networks.

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCConfiguration.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 26 matching lines @@
   RTCRtcpMuxPolicyNegotiate,
   RTCRtcpMuxPolicyRequire
 };
 
 /** Represents the tcp candidate policy. */
 typedef NS_ENUM(NSInteger, RTCTcpCandidatePolicy) {
   RTCTcpCandidatePolicyEnabled,
   RTCTcpCandidatePolicyDisabled
 };
 
+/** Represents the candidate network policy. */
+typedef NS_ENUM(NSInteger, RTCCandidateNetworkPolicy) {
+  RTCCandidateNetworkPolicyAll,
+  RTCCandidateNetworkPolicyLowCost
+};
+
 /** Represents the continual gathering policy. */
 typedef NS_ENUM(NSInteger, RTCContinualGatheringPolicy) {
   RTCContinualGatheringPolicyGatherOnce,
   RTCContinualGatheringPolicyGatherContinually
 };
 
 /** Represents the encryption key type. */
 typedef NS_ENUM(NSInteger, RTCEncryptionKeyType) {
   RTCEncryptionKeyTypeRSA,
   RTCEncryptionKeyTypeECDSA,
@@ skipping 10 matching lines @@
 /** Which candidates the ICE agent is allowed to use. The W3C calls it
  * |iceTransportPolicy|, while in C++ it is called |type|. */
 @property(nonatomic, assign) RTCIceTransportPolicy iceTransportPolicy;
 
 /** The media-bundling policy to use when gathering ICE candidates. */
 @property(nonatomic, assign) RTCBundlePolicy bundlePolicy;
 
 /** The rtcp-mux policy to use when gathering ICE candidates. */
 @property(nonatomic, assign) RTCRtcpMuxPolicy rtcpMuxPolicy;
 @property(nonatomic, assign) RTCTcpCandidatePolicy tcpCandidatePolicy;
+@property(nonatomic, assign) RTCCandidateNetworkPolicy candidateNetworkPolicy;
 @property(nonatomic, assign)
     RTCContinualGatheringPolicy continualGatheringPolicy;
 @property(nonatomic, assign) int audioJitterBufferMaxPackets;
 @property(nonatomic, assign) int iceConnectionReceivingTimeout;
 @property(nonatomic, assign) int iceBackupCandidatePairPingInterval;
 
 /** Key type used to generate SSL identity. Default is ECDSA. */
 @property(nonatomic, assign) RTCEncryptionKeyType keyType;
 
 /** ICE candidate pool size as defined in JSEP. Default is 0. */
 @property(nonatomic, assign) int iceCandidatePoolSize;
 
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 
 @end
 
 NS_ASSUME_NONNULL_END