Make autoclick always left-click on its own tray.

This ensures that autoclick users cannot get locked out of changing
autoclick state because they can always left-click on the autoclick
tray button to change from pause, right-click, etc.

Bug: 894907
Change-Id: I935383b7c03dca0ce9bf31951455a0554706ab62
Reviewed-on: https://chromium-review.googlesource.com/c/1392277
Commit-Queue: Katie Dektar <katie@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620376}
9 files changed