GitLab

This should minimize disruption when a user is writing/sketching
while accidentally holding down the stylus button.

Bug: 767441
Test: ash_unittests --gtest_filter=PaletteTrayTest*
Change-Id: I155d6c7b0997dd56680aaae8a005fba074a15865
Reviewed-on: https://chromium-review.googlesource.com/688486
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504843}