Add paint invalidation for changing high contrast mode.

Bug: 891743

Change-Id: Ia57b767b737d20d5633192696f8c9c6710001704
Reviewed-on: https://chromium-review.googlesource.com/c/1458439
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Tobias Sargeant <tobiasjs@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631243}
5 files changed