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

webrtc/sdk/objc/Framework/UnitTests/RTCConfigurationTest.mm

 /*
  *  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 17 matching lines @@
 - (void)testConversionToNativeConfiguration {
   NSArray *urlStrings = @[ @"stun:stun1.example.net" ];
   RTCIceServer *server = [[RTCIceServer alloc] initWithURLStrings:urlStrings];
 
   RTCConfiguration *config = [[RTCConfiguration alloc] init];
   config.iceServers = @[ server ];
   config.iceTransportPolicy = RTCIceTransportPolicyRelay;
   config.bundlePolicy = RTCBundlePolicyMaxBundle;
   config.rtcpMuxPolicy = RTCRtcpMuxPolicyNegotiate;
   config.tcpCandidatePolicy = RTCTcpCandidatePolicyDisabled;
+  config.candidateNetworkPolicy = RTCCandidateNetworkPolicyLowCost;
   const int maxPackets = 60;
   const int timeout = 1;
   const int interval = 2;
   config.audioJitterBufferMaxPackets = maxPackets;
   config.iceConnectionReceivingTimeout = timeout;
   config.iceBackupCandidatePairPingInterval = interval;
   config.continualGatheringPolicy =
       RTCContinualGatheringPolicyGatherContinually;
 
   std::unique_ptr<webrtc::PeerConnectionInterface::RTCConfiguration>
       nativeConfig([config createNativeConfiguration]);
   EXPECT_TRUE(nativeConfig.get());
   EXPECT_EQ(1u, nativeConfig->servers.size());
   webrtc::PeerConnectionInterface::IceServer nativeServer =
       nativeConfig->servers.front();
   EXPECT_EQ(1u, nativeServer.urls.size());
   EXPECT_EQ("stun:stun1.example.net", nativeServer.urls.front());
 
   EXPECT_EQ(webrtc::PeerConnectionInterface::kRelay, nativeConfig->type);
   EXPECT_EQ(webrtc::PeerConnectionInterface::kBundlePolicyMaxBundle,
             nativeConfig->bundle_policy);
   EXPECT_EQ(webrtc::PeerConnectionInterface::kRtcpMuxPolicyNegotiate,
             nativeConfig->rtcp_mux_policy);
   EXPECT_EQ(webrtc::PeerConnectionInterface::kTcpCandidatePolicyDisabled,
             nativeConfig->tcp_candidate_policy);
+  EXPECT_EQ(webrtc::PeerConnectionInterface::kCandidateNetworkPolicyLowCost,
+            nativeConfig->candidate_network_policy);
   EXPECT_EQ(maxPackets, nativeConfig->audio_jitter_buffer_max_packets);
   EXPECT_EQ(timeout, nativeConfig->ice_connection_receiving_timeout);
   EXPECT_EQ(interval, nativeConfig->ice_backup_candidate_pair_ping_interval);
   EXPECT_EQ(webrtc::PeerConnectionInterface::GATHER_CONTINUALLY,
             nativeConfig->continual_gathering_policy);
 }
 
 @end
 
 TEST(RTCConfigurationTest, NativeConfigurationConversionTest) {
   @autoreleasepool {
     RTCConfigurationTest *test = [[RTCConfigurationTest alloc] init];
     [test testConversionToNativeConfiguration];
   }
 }