Demos of Docked Magnifier + High Contrast with and without fix.

Deleted: dm_hc_without_fix.mp4 749 KB

	dm_hc_without_fix.mp4 749 KB View Download

Deleted: dm_hc_with_fix.mp4 818 KB

	dm_hc_with_fix.mp4 818 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/979ef78e09f6d2ea0b253a011c76289b8a2681bb

commit 979ef78e09f6d2ea0b253a011c76289b8a2681bb
Author: Ahmed Fakhry <afakhry@chromium.org>
Date: Thu Mar 01 19:29:24 2018

Docked Magnifier: Fix High Contrast mode

Before this CL, high contrast was applied to the contents of
the viewport twice (once on the copied contents, and another
since the viewport is a child of the root layer), resulting
in undoing its effect.
This CL updates the "inverted" status of the viewport layer.

BUG= 817431 
TEST=Added test coverage.

Change-Id: I4d946e5ae22f1232db74fecf7b32311073124055
Reviewed-on: https://chromium-review.googlesource.com/942602
Commit-Queue: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540250}
[modify] https://crrev.com/979ef78e09f6d2ea0b253a011c76289b8a2681bb/ash/magnifier/docked_magnifier_controller.cc
[modify] https://crrev.com/979ef78e09f6d2ea0b253a011c76289b8a2681bb/ash/magnifier/docked_magnifier_controller.h
[modify] https://crrev.com/979ef78e09f6d2ea0b253a011c76289b8a2681bb/ash/magnifier/docked_magnifier_controller_unittest.cc
[modify] https://crrev.com/979ef78e09f6d2ea0b253a011c76289b8a2681bb/testing/buildbot/filters/ash_unittests_mash.filter