Update AppService to use crostini API to launch crostini apps.

BUG=1002351

Change-Id: Ib351d0251b0914220d55b269079c958ed06ac9d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1794522Reviewed-by: Nigel Tao <nigeltao@chromium.org>
Commit-Queue: Nancy Wang <nancylingwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695393}

chrome/browser/apps/app_service/crostini_apps.cc

@@ -129,7 +129,7 @@ void CrostiniApps::Launch(const std::string& app_id,
                           int32_t event_flags,
                           apps::mojom::LaunchSource launch_source,
                           int64_t display_id) {
-  apps_util::Launch(app_id, event_flags, launch_source, display_id);
+  crostini::LaunchCrostiniApp(profile_, app_id, display_id);
 }
 
 void CrostiniApps::SetPermission(const std::string& app_id,