lacros: Launch lacros-chrome via upstart when the shelf icon is clicked

For now, always create a new window. Each running lacros browser window
already gets a temporary "running dialog" shelf icon which can be used
to minimize or close the lacros instance.

Bug: 1072472
Test: manual, flip LacrosSideBySide flag, click shelf icon
Change-Id: I006f2e6c2a180092d3f3603d4141a9fd69b29864
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163778Reviewed-by: Erik Chen <erikchen@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762153}

chrome/browser/ui/ash/launcher/lacros_browser_shelf_item_delegate.cc

@@ -5,7 +5,7 @@
 #include "chrome/browser/ui/ash/launcher/lacros_browser_shelf_item_delegate.h"
 
 #include "ash/public/cpp/shelf_types.h"
-#include "base/logging.h"
+#include "chromeos/dbus/upstart/upstart_client.h"
 #include "extensions/common/constants.h"
 
 LacrosBrowserShelfItemDelegate::LacrosBrowserShelfItemDelegate()
@@ -20,7 +20,7 @@ void LacrosBrowserShelfItemDelegate::ItemSelected(
     ItemSelectedCallback callback) {
   // TODO(lacros): Handle window activation, window minimize, and spawning a
   // menu with a list of browser windows.
-  NOTIMPLEMENTED() << "Launch lacros-chrome via upstart";
+  chromeos::UpstartClient::Get()->StartLacrosChrome({"NEW_WINDOW=1"});
   std::move(callback).Run(ash::SHELF_ACTION_NEW_WINDOW_CREATED, {});
 }