This allows to delete non-needed headers from .h files.
Ran this on peer_connection.cc to demonstrate.
Bug: none
Change-Id: I69ce48be25a9778297e521282898c6ac31e7ea6c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/254600
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36170}