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/rtc_tools/BUILD.gn b/rtc_tools/BUILD.gn
index 6269f4c..609598f 100644
--- a/rtc_tools/BUILD.gn
+++ b/rtc_tools/BUILD.gn
@@ -299,6 +299,7 @@
       deps = [
         ":chart_proto",
         "../:webrtc_common",
+        "../api:function_view",
 
         # TODO(kwiberg): Remove this dependency.
         "../api/audio_codecs:audio_codecs_api",