Make shelf item can be dragged when context menu is opened.

ui/views/controls/menu/menu_runner_impl.cc

Index: ui/views/controls/menu/menu_runner_impl.cc
diff --git a/ui/views/controls/menu/menu_runner_impl.cc b/ui/views/controls/menu/menu_runner_impl.cc
index 49c34b6ab7a06e8bffc5fe4f7e6853bd4fba564e..f762c3128ac1a77ee7434791d74dc8639c36b057 100644
--- a/ui/views/controls/menu/menu_runner_impl.cc
+++ b/ui/views/controls/menu/menu_runner_impl.cc
@@ -122,6 +122,10 @@ void MenuRunnerImpl::RunMenuAt(Widget* parent,
     owns_controller_ = true;
   }
   controller->set_is_combobox((run_types & MenuRunner::COMBOBOX) != 0);
+#if defined(OS_CHROMEOS)
+  controller->set_owner_needs_gesture_events(
+      (run_types & MenuRunner::IS_DRAGGABLE) != 0);
+#endif
   controller_ = controller->AsWeakPtr();
   menu_->set_controller(controller_.get());
   menu_->PrepareForRun(owns_controller_,