Don't select audio codecs depending on GN vars `build_with_{chromium|mozilla}`

BUG=webrtc:8343

Change-Id: I5943006a4da17f72eb88eae9d7ea57574d54f680
Reviewed-on: https://webrtc-review.googlesource.com/9401
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20540}
diff --git a/modules/audio_coding/audio_coding.gni b/modules/audio_coding/audio_coding.gni
index 41dcf00..9b0aba8 100644
--- a/modules/audio_coding/audio_coding.gni
+++ b/modules/audio_coding/audio_coding.gni
@@ -20,13 +20,10 @@
 } else {
   audio_codec_defines += [ "WEBRTC_OPUS_SUPPORT_120MS_PTIME=0" ]
 }
-if (!build_with_mozilla) {
-  if (current_cpu == "arm") {
-    audio_codec_defines += [ "WEBRTC_CODEC_ISACFX" ]
-  } else {
-    audio_codec_defines += [ "WEBRTC_CODEC_ISAC" ]
-  }
-  audio_codec_defines += [ "WEBRTC_CODEC_G722" ]
+if (current_cpu == "arm") {
+  audio_codec_defines += [ "WEBRTC_CODEC_ISACFX" ]
+} else {
+  audio_codec_defines += [ "WEBRTC_CODEC_ISAC" ]
 }
 if (!build_with_mozilla && !build_with_chromium) {
   audio_codec_defines += [ "WEBRTC_CODEC_RED" ]