Make CodecType conversion functions non-optional.

webrtc/video/send_statistics_proxy.cc

Index: webrtc/video/send_statistics_proxy.cc
diff --git a/webrtc/video/send_statistics_proxy.cc b/webrtc/video/send_statistics_proxy.cc
index a6f421ae042a882dfd9bbd90175bf81bfbbdcfe6..3b973435226f756eec241ca23b8121ad0c9b95fd 100644
--- a/webrtc/video/send_statistics_proxy.cc
+++ b/webrtc/video/send_statistics_proxy.cc
@@ -50,12 +50,8 @@ const char* GetUmaPrefix(VideoEncoderConfig::ContentType content_type) {
 
 HistogramCodecType PayloadNameToHistogramCodecType(
     const std::string& payload_name) {
-  rtc::Optional<VideoCodecType> codecType =
-      PayloadNameToCodecType(payload_name);
-  if (!codecType) {
-    return kVideoUnknown;
-  }
-  switch (*codecType) {
+  VideoCodecType codecType = PayloadStringToCodecType(payload_name);
+  switch (codecType) {
     case kVideoCodecVP8:
       return kVideoVp8;
     case kVideoCodecVP9: