Reland of move deprecated CodecType methods. (patchset #1 id:1 of https://codereview.webrtc.org/3010553002/ )

Reason for revert:
Fixes have landed in chromium.

Original issue's description:
> Revert of Remove deprecated CodecType methods. (patchset #1 id:1 of https://codereview.webrtc.org/3009583002/ )
>
> Reason for revert:
> It breaks chromium FYI bots.
>
> E.g.: https://build.chromium.org/p/chromium.webrtc.fyi/builders/Win%20Builder/builds/11615
>
> Original issue's description:
> > Remove deprecated CodecType methods.
> >
> > These are no longer needed as all clients have been updated to use the
> > new methods that always return a value.
> >
> > BUG=None
> >
> > Review-Url: https://codereview.webrtc.org/3009583002
> > Cr-Commit-Position: refs/heads/master@{#19559}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/1a92d0de49779567241e97e50cb69d51257adcce
>
> TBR=magjed@webrtc.org,tommi@webrtc.org,kthelgason@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=None
>
> Review-Url: https://codereview.webrtc.org/3010553002
> Cr-Commit-Position: refs/heads/master@{#19563}
> Committed: https://chromium.googlesource.com/external/webrtc/+/673caedc39f8fc0975fb902041c9000c271bfccf

TBR=magjed@webrtc.org,tommi@webrtc.org,mbonadei@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=None

Review-Url: https://codereview.webrtc.org/3009413002
Cr-Original-Commit-Position: refs/heads/master@{#19816}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: dc80abe975e9523c9bb3eba65240538ee2478c72
diff --git a/common_types.cc b/common_types.cc
index 1ea4099..7a27fcb 100644
--- a/common_types.cc
+++ b/common_types.cc
@@ -178,16 +178,6 @@
   return kVideoCodecGeneric;
 }
 
-// TODO(kthelgason): Remove these methods once upstream projects
-// have been updated.
-rtc::Optional<const char*> CodecTypeToPayloadName(VideoCodecType type) {
-  return rtc::Optional<const char*>(CodecTypeToPayloadString(type));
-}
-
-rtc::Optional<VideoCodecType> PayloadNameToCodecType(const std::string& name) {
-  return rtc::Optional<VideoCodecType>(PayloadStringToCodecType(name));
-}
-
 const uint32_t BitrateAllocation::kMaxBitrateBps =
     std::numeric_limits<uint32_t>::max();
 
diff --git a/common_types.h b/common_types.h
index e5bd9a8..9ad5165 100644
--- a/common_types.h
+++ b/common_types.h
@@ -554,10 +554,6 @@
 // Translates from name of codec to codec type and vice versa.
 const char* CodecTypeToPayloadString(VideoCodecType type);
 VideoCodecType PayloadStringToCodecType(const std::string& name);
-// TODO(kthelgason): Remove these methods once upstream projects
-// have been updated.
-rtc::Optional<const char*> CodecTypeToPayloadName(VideoCodecType type);
-rtc::Optional<VideoCodecType> PayloadNameToCodecType(const std::string& name);
 
 union VideoCodecUnion {
   VideoCodecVP8 VP8;