GitLab

Use a top priority pre-target handler in Seat class to track
pressed keys. This is needed to ensure that we see all key events.

Also cleanup some of the code in Keyboard class where we send
modifiers. It doesn't make sense to send modifiers in cases
where the key event is a reserved accelerator and won't be
delivered to the client.

Bug: 820641
Test: exo_unittests --gtest_filter=KeyboardTest.OnKeyboardEnter
Change-Id: Ib1169a7c0ad70e8e7973c94edf4b9885fecc7819
Reviewed-on: https://chromium-review.googlesource.com/1001634Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549364}