BUILD.gn file for api/audio.

Targets containing files in api/audio are moved from api/BUILD.gn to
api/audio/BUILD.gn.

Bug: webrtc:8844
Change-Id: Ib7ea4b7eb3c2ea38ef8261a1fc5c2b4674985981
Reviewed-on: https://webrtc-review.googlesource.com/54360
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22074}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index 78a5137..5eef0e1 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -29,10 +29,10 @@
 
   deps = [
     # TODO(kjellander): Add remaining dependencies when webrtc:4243 is done.
-    ":audio_mixer_api",
     ":transport_api",
     "..:webrtc_common",
     "../rtc_base:rtc_base_approved",
+    "audio:audio_mixer_api",
     "audio_codecs:audio_codecs_api",
   ]
 }
@@ -100,13 +100,13 @@
 
   deps = [
     ":array_view",
-    ":audio_mixer_api",
     ":audio_options_api",
     ":callfactory_api",
     ":libjingle_logging_api",
     ":optional",
     ":rtc_stats_api",
     ":video_frame_api",
+    "audio:audio_mixer_api",
     "audio_codecs:audio_codecs_api",
 
     # Basically, don't add stuff here. You might break sensitive downstream
@@ -192,60 +192,6 @@
   ]
 }
 
-rtc_source_set("audio_frame_api") {
-  visibility = [ "*" ]
-  sources = [
-    "audio/audio_frame.cc",
-    "audio/audio_frame.h",
-  ]
-
-  deps = [
-    "../:typedefs",
-    "../rtc_base:checks",
-    "../rtc_base:deprecation",
-    "../rtc_base:rtc_base_approved",
-  ]
-}
-
-rtc_source_set("audio_mixer_api") {
-  visibility = [ "*" ]
-  sources = [
-    "audio/audio_mixer.h",
-  ]
-
-  deps = [
-    ":audio_frame_api",
-    "../rtc_base:rtc_base_approved",
-  ]
-}
-
-rtc_source_set("aec3_config") {
-  visibility = [ "*" ]
-  sources = [
-    "audio/echo_canceller3_config.h",
-  ]
-}
-
-rtc_source_set("aec3_factory") {
-  visibility = [ "*" ]
-  sources = [
-    "audio/echo_canceller3_factory.cc",
-    "audio/echo_canceller3_factory.h",
-  ]
-
-  deps = [
-    ":aec3_config",
-    ":echo_control",
-  ]
-}
-
-rtc_source_set("echo_control") {
-  visibility = [ "*" ]
-  sources = [
-    "audio/echo_control.h",
-  ]
-}
-
 rtc_source_set("audio_options_api") {
   visibility = [ "*" ]
   sources = [
@@ -367,8 +313,8 @@
     ]
 
     deps = [
-      ":audio_mixer_api",
       "../test:test_support",
+      "audio:audio_mixer_api",
     ]
   }