Launch Crostini apps with display scaled up.

This CL adds logic to check the app preference and to send app launch
request with display scaled up if the preference is set to scaled
display.

BUG=chromium:839242
TEST=Manually tested on an eve device.

Change-Id: I054d384161219a1596aee4366d9bc56962b87eb3
Reviewed-on: https://chromium-review.googlesource.com/1232754
Reviewed-by: Nicholas Verne <nverne@chromium.org>
Commit-Queue: Tim Zheng <timzheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592587}
3 files changed