overlord: ui: implement terminal window maximize function

Allow user to maximize terminal window. Remove the terminal resize
function since it's broken.

BUG=chromium:503673
TEST=manually

Change-Id: Ia3061a5b6ccdcd1e4c2e78c43d71d5b79e3b2fff
Reviewed-on: https://chromium-review.googlesource.com/337583
Commit-Ready: Wei-Ning Huang <wnhuang@chromium.org>
Tested-by: Wei-Ning Huang <wnhuang@chromium.org>
Reviewed-by: Wei-Han Chen <stimim@chromium.org>
10 files changed