[Lacros] Add tabbed window mode in app service.

This CL adds tabbed window mode in the app service window mode, and
update the code in context menu and app list to use app service instead
of directly querying the web app provider which remove the direct
call from ash-chrome to lacros-chrome.

BUG=1144877

Change-Id: Ie918c9b1529b2c0d3113aaf3740eba7448312cee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2943913
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Reviewed-by: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#890593}