ozone/platform/wayland: Add support for wl_output_interface

WaylandScreen is used to keep track of the current outputs
(display) that are available to Wayland clients.

This is a part of upstream work for the ozone-wayland project:
https://github.com/01org/ozone-wayland

BUG=578890
TEST=WaylandDisplayTest.Output

Review-Url: https://codereview.chromium.org/2042503002
Cr-Commit-Position: refs/heads/master@{#421157}
10 files changed