Split voe::Channel into ChannelSend and ChannelReceive

Bug: webrtc:9801
Change-Id: Ia15af1e53c8d384ad6e5fbddcb25311fce4befae
Reviewed-on: https://webrtc-review.googlesource.com/c/103640
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24992}
diff --git a/audio/BUILD.gn b/audio/BUILD.gn
index e42a726..91cece9 100644
--- a/audio/BUILD.gn
+++ b/audio/BUILD.gn
@@ -24,10 +24,12 @@
     "audio_state.h",
     "audio_transport_impl.cc",
     "audio_transport_impl.h",
-    "channel.cc",
-    "channel.h",
+    "channel_receive.cc",
+    "channel_receive.h",
     "channel_receive_proxy.cc",
     "channel_receive_proxy.h",
+    "channel_send.cc",
+    "channel_send.h",
     "channel_send_proxy.cc",
     "channel_send_proxy.h",
     "conversion.h",