Optofidelity: PWM compensation

If PWM is recognized, we trim the color of the screen to the lowest
color shown in the reference image. This way the artifacts will no
longer be visible during processing.

BUG=chromium:505519
TEST=None

Change-Id: I64db211c1ad8964a24da1bca52c5c7b1caf46c89
Reviewed-on: https://chromium-review.googlesource.com/336464
Commit-Ready: Dennis Kempin <denniskempin@chromium.org>
Tested-by: Dennis Kempin <denniskempin@chromium.org>
Reviewed-by: Dennis Kempin <denniskempin@chromium.org>
4 files changed