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/BUILD.gn b/pc/BUILD.gn
index 280e077..2b4d111 100644
--- a/pc/BUILD.gn
+++ b/pc/BUILD.gn
@@ -355,6 +355,7 @@
     ]
     deps = [
       ":pc_test_utils",
+      "../api:function_view",
       "../api:libjingle_peerconnection_api",
       "../api:rtc_stats_api",
       "../api:scoped_refptr",
@@ -490,6 +491,7 @@
       "../api:create_peerconnection_factory",
       "../api:fake_frame_decryptor",
       "../api:fake_frame_encryptor",
+      "../api:function_view",
       "../api:libjingle_logging_api",
       "../api:libjingle_peerconnection_api",
       "../api:loopback_media_transport",
diff --git a/pc/peer_connection_wrapper.cc b/pc/peer_connection_wrapper.cc
index 6bfb59f..74089f6 100644
--- a/pc/peer_connection_wrapper.cc
+++ b/pc/peer_connection_wrapper.cc
@@ -16,11 +16,11 @@
 #include <utility>
 #include <vector>
 
+#include "api/function_view.h"
 #include "api/set_remote_description_observer_interface.h"
 #include "pc/sdp_utils.h"
 #include "pc/test/fake_video_track_source.h"
 #include "rtc_base/checks.h"
-#include "rtc_base/function_view.h"
 #include "rtc_base/gunit.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/ref_counted_object.h"
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 {