GitLab

Instead of firing custom events when dropdown selections are changed,
use data bindings to set the scanning-app element's properties to the
selected values.

Bug: 1059779
Test: Select a scanner and verify its capabilities are obtained.
Change-Id: If8927a4898dca25720c7f8550fe640fad160178a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2448668Reviewed-by: Jimmy Gong <jimmyxgong@chromium.org>
Commit-Queue: Jesse Schettler <jschettler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813959}