Introduce struct MediaConfig, with construction-time settings.

webrtc/api/peerconnection.cc

 /*
  *  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 598 matching lines @@
 
   if (configuration.tcp_candidate_policy == kTcpCandidatePolicyDisabled) {
     portallocator_flags |= cricket::PORTALLOCATOR_DISABLE_TCP;
     LOG(LS_INFO) << "TCP candidates are disabled.";
   }
 
   port_allocator_->set_flags(portallocator_flags);
   // No step delay is used while allocating ports.
   port_allocator_->set_step_delay(cricket::kMinimumStepDelay);
 
-  media_controller_.reset(factory_->CreateMediaController());
+  // We rely on default values when constraints aren't found.
+  cricket::MediaConfig media_config;
+
+  media_config.disable_prerenderer_smoothing =
+      configuration.disable_prerenderer_smoothing;
+
+  // Find DSCP constraint.
+  FindConstraint(constraints, MediaConstraintsInterface::kEnableDscp,
+                 &media_config.enable_dscp, NULL);
+  // Find constraints for cpu overuse detection.
+  FindConstraint(constraints, MediaConstraintsInterface::kCpuOveruseDetection,
+                 &media_config.enable_cpu_overuse_detection, NULL);
+
+  media_controller_.reset(factory_->CreateMediaController(media_config));
 
   remote_stream_factory_.reset(new RemoteMediaStreamFactory(
       factory_->signaling_thread(), media_controller_->channel_manager()));
 
   session_.reset(
       new WebRtcSession(media_controller_.get(), factory_->signaling_thread(),
                         factory_->worker_thread(), port_allocator_.get()));
   stats_.reset(new StatsCollector(this));
 
   // Initialize the WebRtcSession. It creates transport channels etc.
@@ skipping 1435 matching lines @@
 DataChannel* PeerConnection::FindDataChannelBySid(int sid) const {
   for (const auto& channel : sctp_data_channels_) {
     if (channel->id() == sid) {
       return channel;
     }
   }
   return nullptr;
 }
 
 }  // namespace webrtc