Discard pinning an app with non-empty launcher id.

chrome/browser/ui/ash/launcher/launcher_item_controller.h

Index: chrome/browser/ui/ash/launcher/launcher_item_controller.h
diff --git a/chrome/browser/ui/ash/launcher/launcher_item_controller.h b/chrome/browser/ui/ash/launcher/launcher_item_controller.h
index 3661e81c400177175416a36ad13adea03272ee65..1fd2a83259ef6f0eac55fac5d58e36700173b4d9 100644
--- a/chrome/browser/ui/ash/launcher/launcher_item_controller.h
+++ b/chrome/browser/ui/ash/launcher/launcher_item_controller.h
@@ -19,6 +19,8 @@ class ChromeLauncherController;
 
 // LauncherItemController is used by ChromeLauncherController to track one
 // or more windows associated with a shelf item.
+// TODO (khmel): Consider using ash::launcher::AppLauncherId instead of pair
+// |app_id| and |launch_id|.
 class LauncherItemController : public ash::ShelfItemDelegate {
  public:
   LauncherItemController(const std::string& app_id,