Use field_trial::IsEnabled for FlexFEC.

webrtc/media/engine/webrtcvideoengine2.cc

 /*
  *  Copyright (c) 2014 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 @@
 #include "webrtc/media/engine/webrtcvideoencoderfactory.h"
 #include "webrtc/media/engine/webrtcvoiceengine.h"
 #include "webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.h"
 #include "webrtc/system_wrappers/include/field_trial.h"
 
 using DegradationPreference = webrtc::VideoSendStream::DegradationPreference;
 
 namespace cricket {
 namespace {
 // If this field trial is enabled, we will enable sending FlexFEC and disable
-// sending ULPFEC whenever the former has been negotiated. Receiving FlexFEC
-// is enabled whenever FlexFEC has been negotiated.
+// sending ULPFEC whenever the former has been negotiated.
+// FlexFEC can only be negotiated when the "flexfec-03" SDP codec is enabled,
+// which is done by enabling the "WebRTC-FlexFEC-03-Advertised" field trial; see
+// internalencoderfactory.cc.
 bool IsFlexfecFieldTrialEnabled() {
-  return webrtc::field_trial::FindFullName("WebRTC-FlexFEC-03") == "Enabled";
+  return webrtc::field_trial::IsEnabled("WebRTC-FlexFEC-03");
 }
 
 // If this field trial is enabled, we will report VideoContentType RTP extension
 // in capabilities (thus, it will end up in the default SDP and extension will
 // be sent for all key-frames).
 bool IsVideoContentTypeExtensionFieldTrialEnabled() {
   return webrtc::field_trial::IsEnabled("WebRTC-VideoContentTypeExtension");
 }
 
 // Wrap cricket::WebRtcVideoEncoderFactory as a webrtc::VideoEncoderFactory.
@@ skipping 2537 matching lines @@
         rtx_mapping[video_codecs[i].codec.id] !=
             ulpfec_config.red_payload_type) {
       video_codecs[i].rtx_payload_type = rtx_mapping[video_codecs[i].codec.id];
     }
   }
 
   return video_codecs;
 }
 
 }  // namespace cricket