Use app ID instead of startup ID for display.

This change switch to use Crostini app ID instead of the startup ID to
track the display that the apps are started from.
There are Crostini apps that don't implement the startup notification
protocol but can be linked with their application ID. This change will
make those apps start in the correct display.

BUG=chromium:843001
TEST=Manually tested on an eve device.

Change-Id: I6033f9fdc187dede9138c20be7935c6e9a802f8c
Reviewed-on: https://chromium-review.googlesource.com/1125515
Commit-Queue: Nicholas Verne <nverne@chromium.org>
Reviewed-by: Nicholas Verne <nverne@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573156}
6 files changed