Make CodecType conversion functions non-optional.

webrtc/media/engine/internalencoderfactory.cc

Index: webrtc/media/engine/internalencoderfactory.cc
diff --git a/webrtc/media/engine/internalencoderfactory.cc b/webrtc/media/engine/internalencoderfactory.cc
index a8d4f2d2c2c935282d0699cb0aeaabb441b54653..004db791609647b69981d8397c4e1d5517ba9a32 100644
--- a/webrtc/media/engine/internalencoderfactory.cc
+++ b/webrtc/media/engine/internalencoderfactory.cc
@@ -71,8 +71,7 @@ InternalEncoderFactory::~InternalEncoderFactory() {}
 webrtc::VideoEncoder* InternalEncoderFactory::CreateVideoEncoder(
     const cricket::VideoCodec& codec) {
   const webrtc::VideoCodecType codec_type =
-      webrtc::PayloadNameToCodecType(codec.name)
-          .value_or(webrtc::kVideoCodecUnknown);
+      webrtc::PayloadStringToCodecType(codec.name);
   switch (codec_type) {
     case webrtc::kVideoCodecH264:
       return webrtc::H264Encoder::Create(codec);