Revert "Changes to build inside a Dawn checkout." This reverts commit 11c31e0a4a73d7d62e765dc7ec400560fbb16b5e. Reason for revert: Broke ANGLE -> Skia roll because of GN error. Bug: angleproject:5489 Original change's description: > Changes to build inside a Dawn checkout. > > Add an "angle_standalone" flag that can be disabled by Dawn. > Put test definitions behind angle_standalone || build_with_chromium. > > Bug: angleproject:5462 > Change-Id: I58c9b18723384334156e2a3dd86ed3f89afcaade > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2587451 > Reviewed-by: Jamie Madill <jmadill@chromium.org> > Commit-Queue: Stephen White <senorblanco@chromium.org> TBR=senorblanco@chromium.org,jmadill@chromium.org # Not skipping CQ checks because original CL landed > 1 day ago. Bug: angleproject:5462 Change-Id: I4363d1d35b03e00d970e25ddd3d7eac51ad2da2d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2600078 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>