GitLab

Extends the wl_pointer protocol using the wayland upstream
zwp_pointer_gestures protocol to pass information about pinch gestures.

BUG=b:25668308

Change-Id: I9f90ebebec3f8476181e0426401827a3cf1064e4
Reviewed-on: https://chromium-review.googlesource.com/699017
Commit-Queue: Sean O'Brien <seobrien@chromium.org>
Reviewed-by: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506828}