This makes it easier to add options to this script.

There should be no functional changes except for slightly different
text output.

Change-Id: I4d68a8c4aa0c159eae9435fe962e53f6f09d2d47
Reviewed-on: https://chromium-review.googlesource.com/499527
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>