Simplifies boolean logic since shortcuts mean most will never be
executed and also replaces variables with constants to improve
readability.

Change-Id: Ic1678bc60c3e85daced758ce139f7d03c25632dc
Reviewed-on: https://chromium-review.googlesource.com/928320Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51419}