Reimplement the builtin audio codec factories using the new stuff in api/

webrtc/modules/audio_coding/BUILD.gn

Index: webrtc/modules/audio_coding/BUILD.gn
diff --git a/webrtc/modules/audio_coding/BUILD.gn b/webrtc/modules/audio_coding/BUILD.gn
index 3e6a1834868daa33c7d2f9f2bf3d8460d665e4df..a3964c90804e9aa0618e65f7dfe0a6fc3887bde1 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -51,34 +51,6 @@ rtc_static_library("audio_format_conversion") {
   ]
 }
 
-rtc_static_library("builtin_audio_decoder_factory_internal") {
-  sources = [
-    "codecs/builtin_audio_decoder_factory_internal.cc",
-    "codecs/builtin_audio_decoder_factory_internal.h",
-  ]
-  deps = [
-           "../..:webrtc_common",
-           "../../rtc_base:protobuf_utils",
-           "../../rtc_base:rtc_base_approved",
-           "../../api/audio_codecs:audio_codecs_api",
-         ] + audio_codec_deps
-  defines = audio_codec_defines
-}
-
-rtc_static_library("builtin_audio_encoder_factory_internal") {
-  sources = [
-    "codecs/builtin_audio_encoder_factory_internal.cc",
-    "codecs/builtin_audio_encoder_factory_internal.h",
-  ]
-  deps = [
-           "../..:webrtc_common",
-           "../../rtc_base:protobuf_utils",
-           "../../rtc_base:rtc_base_approved",
-           "../../api/audio_codecs:audio_codecs_api",
-         ] + audio_codec_deps
-  defines = audio_codec_defines
-}
-
 rtc_static_library("rent_a_codec") {
   sources = [
     "acm2/acm_codec_database.cc",
@@ -840,13 +812,13 @@ rtc_static_library("webrtc_opus") {
     "../../api/audio_codecs:audio_codecs_api",
     "../../api/audio_codecs/opus:audio_encoder_opus_config",
     "../../common_audio",
-    "../../rtc_base:protobuf_utils",
     "../../rtc_base:rtc_base_approved",
     "../../rtc_base:rtc_numerics",
     "../../system_wrappers",
   ]
   public_deps = [
     ":webrtc_opus_c",
+    "../../rtc_base:protobuf_utils",
   ]
 
   defines = audio_codec_defines