Expand is_linux to is_linux || is_chromeos. Currently is_linux is set to true on Chrome OS build, but it is planned to set to false. This CL is the preparation to keep the current behavior. Bug: chromium:1110266 Test: Built locally. Tryjob. Change-Id: I4124dfb251d68a519fed3e08555d1aa5a694c77c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2404500 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>