[ozone/wayland] implement key auto repeat

CL implements key auto repeat functionality to Ozone/Wayland
by making use of ui::EventAutoRepeatHandler class and its delegate
logic.

In the specific case of Wayland, it is important to async-await on
the compositor before doing auto repeats, so that any missing key
up events get a chance to be processed under janky situations.

Bug: 578890
Change-Id: I63e38851e8d07528c46778d80c5f5163b7fceabd
Reviewed-on: https://chromium-review.googlesource.com/874670
Reviewed-by: Michael Spang <spang@chromium.org>
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#531595}
7 files changed