Remove rtc_base/scoped_ref_ptr.h.

The type rtc::scoped_refptr<T> is now part of api/. Please include it from
api/scoped_refptr.h.

More info: See: https://groups.google.com/forum/#!topic/discuss-webrtc/Mme2MSz4z4o.

Bug: webrtc:9887, webrtc:8205
No-Try: True
Change-Id: Ic6c7c81e226e59f12f7933e472f573ae097b55bf
Reviewed-on: https://webrtc-review.googlesource.com/c/119041
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26414}
diff --git a/audio/BUILD.gn b/audio/BUILD.gn
index 116385e..e4ab39a 100644
--- a/audio/BUILD.gn
+++ b/audio/BUILD.gn
@@ -46,6 +46,7 @@
     "../api:array_view",
     "../api:call_api",
     "../api:libjingle_peerconnection_api",
+    "../api:scoped_refptr",
     "../api:transport_api",
     "../api/audio:aec3_factory",
     "../api/audio:audio_frame_api",