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 57d7cd924736e6627a0b36ff75dad4ef66875214..158e806b0dac06608c4d2b6456c29647ed1e0eed 100644
--- a/webrtc/modules/audio_coding/BUILD.gn
+++ b/webrtc/modules/audio_coding/BUILD.gn
@@ -187,6 +187,13 @@ rtc_source_set("red") {
   ]
 }
 
+rtc_source_set("audio_coding_utils") {
+  sources = [
+    "codecs/split_by_samples.cc",
+    "codecs/split_by_samples.h",
+  ]
+}
+
 config("g711_config") {
   include_dirs = [
     "../../..",
@@ -209,6 +216,7 @@ rtc_source_set("g711") {
   public_configs = [ ":g711_config" ]
 
   deps = [
+    ":audio_coding_utils",
     ":audio_decoder_interface",
     ":audio_encoder_interface",
   ]
@@ -237,6 +245,7 @@ rtc_source_set("g722") {
   public_configs = [ ":g722_config" ]
 
   deps = [
+    ":audio_coding_utils",
     ":audio_decoder_interface",
     ":audio_encoder_interface",
   ]