Add missed include <atomic> Following https://crrev.com/c/4886388 Bug: b/302112423 Change-Id: I8d9c1269d5e2470ee9f559eae26eddeb8a956a9d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4904696 Commit-Queue: Roman Lavrov <romanl@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>