GitLab

  - Adds detection and dispatch of screen entry/exit events.
  - Adds detection of a finger press and hold in the corner.
  - Better handling of multiple-finger events on the screen.

Bug: internal b/112073644
Bug: internal b/112314035
Test: unit test and manual
Change-Id: Id2155f8e432428ee63f3457274f1507ce1edee53
Reviewed-on: https://chromium-review.googlesource.com/1165795Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Reviewed-by: Kevin Schoedel <kpschoedel@chromium.org>
Commit-Queue: Ryan Daum <rdaum@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582196}