Moved codec-specific audio packet splitting into decoders.

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 b6e2db3ac359d723222373521be4d7ca964e18cf..a18667019a3500fede5f1db4364100aff28c775c 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -130,6 +130,7 @@ rtc_source_set("audio_decoder_interface") {
     "codecs/audio_decoder.h",
   ]
   deps = [
+    ":legacy_encoded_audio_frame",
     "../..:webrtc_common",
     "../../base:rtc_base_approved",
   ]
@@ -187,6 +188,13 @@ rtc_source_set("red") {
   ]
 }
 
+rtc_source_set("legacy_encoded_audio_frame") {
+  sources = [
+    "codecs/legacy_encoded_audio_frame.cc",
+    "codecs/legacy_encoded_audio_frame.h",
+  ]
+}
+
 config("g711_config") {
   include_dirs = [
     "../../..",
@@ -211,6 +219,7 @@ rtc_source_set("g711") {
   deps = [
     ":audio_decoder_interface",
     ":audio_encoder_interface",
+    ":legacy_encoded_audio_frame",
   ]
 }
 
@@ -239,6 +248,7 @@ rtc_source_set("g722") {
   deps = [
     ":audio_decoder_interface",
     ":audio_encoder_interface",
+    ":legacy_encoded_audio_frame",
   ]
 }