message: build: remove WEBRTC_CODEC_RED
  gone for a while
  Cr-Commit-Position: refs/heads/master@{#31352}
diff: @@ -25,9 +25,6 @@ if (current_cpu == "arm") {
  } else {
  audio_codec_defines += [ "WEBRTC_CODEC_ISAC" ]
  }
  -if (!build_with_mozilla && !build_with_chromium) {
  - audio_codec_defines += [ "WEBRTC_CODEC_RED" ]
  -}
  audio_coding_defines = audio_codec_defines
  neteq_defines = audio_codec_defines
  