Clear out cached codecs when calculating new codec lists.

webrtc/media/engine/webrtcvideoencoderfactory.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
 #include "webrtc/media/engine/webrtcvideoencoderfactory.h"
 
 #include "webrtc/common_types.h"
 
 namespace cricket {
 
 webrtc::VideoEncoder* WebRtcVideoEncoderFactory::CreateVideoEncoder(
     const cricket::VideoCodec& codec) {
   return CreateVideoEncoder(webrtc::PayloadNameToCodecType(codec.name)
                                 .value_or(webrtc::kVideoCodecUnknown));
 }
 
 const std::vector<cricket::VideoCodec>&
 WebRtcVideoEncoderFactory::supported_codecs() const {
+  codecs_.clear();
   const std::vector<VideoCodec>& encoder_codecs = codecs();
   for (const VideoCodec& encoder_codec : encoder_codecs) {
     codecs_.push_back(cricket::VideoCodec(encoder_codec.name));
   }
   return codecs_;
 }
 
 webrtc::VideoEncoder* WebRtcVideoEncoderFactory::CreateVideoEncoder(
     webrtc::VideoCodecType type) {
   const cricket::VideoCodec codec(
       webrtc::CodecTypeToPayloadName(type).value_or("Unknown codec"));
   return CreateVideoEncoder(codec);
 }
 
 const std::vector<WebRtcVideoEncoderFactory::VideoCodec>&
 WebRtcVideoEncoderFactory::codecs() const {
+  encoder_codecs_.clear();
   const std::vector<cricket::VideoCodec>& codecs = supported_codecs();
   for (const cricket::VideoCodec& codec : codecs) {
     encoder_codecs_.push_back(
         VideoCodec(webrtc::PayloadNameToCodecType(codec.name)
                        .value_or(webrtc::kVideoCodecUnknown),
                    codec.name));
   }
   return encoder_codecs_;
 }
 
 }  // namespace cricket