Add "max_ipv6_networks" field to RTCConfiguration.

webrtc/api/peerconnectioninterface.h

 /*
  *  Copyright 2012 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 334 matching lines @@
     // TODO(deadbeef): Remove this? IPv6 support has long stopped being
     // experimental
     bool disable_ipv6 = false;
 
     // If set to true, don't gather IPv6 ICE candidates on Wi-Fi.
     // Only intended to be used on specific devices. Certain phones disable IPv6
     // when the screen is turned off and it would be better to just disable the
     // IPv6 ICE candidates on Wi-Fi in those cases.
     bool disable_ipv6_on_wifi = false;
 
+    // By default, the PeerConnection will use a limited number of IPv6 network
+    // interfaces, in order to avoid too many ICE candidate pairs being created
+    // and delaying ICE completion.
+    //
+    // Can be set to INT_MAX to effectively disable the limit.
+    int max_ipv6_networks = cricket::kDefaultMaxIPv6Networks;
+
     // If set to true, use RTP data channels instead of SCTP.
     // TODO(deadbeef): Remove this. We no longer commit to supporting RTP data
     // channels, though some applications are still working on moving off of
     // them.
     bool enable_rtp_data_channel = false;
 
     // Minimum bitrate at which screencast video tracks will be encoded at.
     // This means adding padding bits up to this bitrate, which can help
     // when switching from a static scene to one with motion.
     rtc::Optional<int> screencast_min_bitrate;
@@ skipping 840 matching lines @@
     cricket::WebRtcVideoEncoderFactory* video_encoder_factory,
     cricket::WebRtcVideoDecoderFactory* video_decoder_factory,
     rtc::scoped_refptr<AudioMixer> audio_mixer,
     std::unique_ptr<cricket::MediaEngineInterface> media_engine,
     std::unique_ptr<CallFactoryInterface> call_factory,
     std::unique_ptr<RtcEventLogFactoryInterface> event_log_factory);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_PEERCONNECTIONINTERFACE_H_