Move rtc::FunctionView to the public API

Bug: webrtc:10138
Change-Id: Icc25a2a277a9608701aaddd546882366739991ca
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/127898
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27227}
diff --git a/pc/peer_connection_wrapper.h b/pc/peer_connection_wrapper.h
index d7f10b4..fafee24 100644
--- a/pc/peer_connection_wrapper.h
+++ b/pc/peer_connection_wrapper.h
@@ -16,6 +16,7 @@
 #include <vector>
 
 #include "api/data_channel_interface.h"
+#include "api/function_view.h"
 #include "api/jsep.h"
 #include "api/media_stream_interface.h"
 #include "api/media_types.h"
@@ -26,7 +27,6 @@
 #include "api/scoped_refptr.h"
 #include "api/stats/rtc_stats_report.h"
 #include "pc/test/mock_peer_connection_observers.h"
-#include "rtc_base/function_view.h"
 
 namespace webrtc {