chromiumos: restore common.PrepareForBuildResponse

Various places in recipes still use this.

BUG=chromium:1034529
TEST=generate, train

Change-Id: I3f3337fea198cccce90fdf5fc2396443f47bf854
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2172710
Tested-by: LaMont Jones <lamontjones@chromium.org>
Reviewed-by: Sean Abraham <seanabraham@chromium.org>
Commit-Queue: LaMont Jones <lamontjones@chromium.org>
2 files changed