The absl/flags/flag.h header is not #including absl/flags/declare.h starting from [1] so this transitive #include needs to be removed. [1] - https://chromium-review.googlesource.com/c/chromium/src/+/2228841 Bug: None Change-Id: I06e78ed05e0fb570a9ecc8621ec3ae5298fffd1a Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176444 Reviewed-by: Artem Titov <titovartem@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#31433}