mash: Use mojo for ShelfItemDelegate and [app] MenuItem.

ash/common/shelf/wm_shelf.cc

Index: ash/common/shelf/wm_shelf.cc
diff --git a/ash/common/shelf/wm_shelf.cc b/ash/common/shelf/wm_shelf.cc
index 2a06cc21baa5039b55009c07e6ae45d745dd18c5..ef3339764279aafe32e92022663040c620f228fa 100644
--- a/ash/common/shelf/wm_shelf.cc
+++ b/ash/common/shelf/wm_shelf.cc
@@ -27,6 +27,13 @@
 
 namespace ash {
 
+namespace {
+
+// A callback that does nothing after shelf item selection handling.
+void NoopCallback(ShelfAction, ShelfItemDelegate::MenuItemList) {}
+
+}  // namespace
+
 // WmShelf::AutoHideEventHandler -----------------------------------------------
 
 // Forwards mouse and gesture events to ShelfLayoutManager for auto-hide.
@@ -292,8 +299,10 @@ void WmShelf::ActivateShelfItem(int item_index) {
   ShelfModel* shelf_model = WmShell::Get()->shelf_model();
   const ShelfItem& item = shelf_model->items()[item_index];
   ShelfItemDelegate* item_delegate = shelf_model->GetShelfItemDelegate(item.id);
-  item_delegate->ItemSelected(ui::ET_KEY_RELEASED, ui::EF_NONE,
-                              display::kInvalidDisplayId, LAUNCH_FROM_UNKNOWN);
+  std::unique_ptr<ui::Event> event = base::MakeUnique<ui::KeyEvent>(
+      ui::ET_KEY_RELEASED, ui::VKEY_UNKNOWN, ui::EF_NONE);
+  item_delegate->ItemSelected(std::move(event), display::kInvalidDisplayId,
+                              LAUNCH_FROM_UNKNOWN, base::Bind(&NoopCallback));
 }
 
 bool WmShelf::ProcessGestureEvent(const ui::GestureEvent& event) {