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

ash/shell/window_watcher_shelf_item_delegate.h

Index: ash/shell/window_watcher_shelf_item_delegate.h
diff --git a/ash/shell/window_watcher_shelf_item_delegate.h b/ash/shell/window_watcher_shelf_item_delegate.h
index 73bb422c1f5ec28299c8c7c5e2ba8d42c0e261be..1472356d7545007578e2537f594c20c10ba0fd54 100644
--- a/ash/shell/window_watcher_shelf_item_delegate.h
+++ b/ash/shell/window_watcher_shelf_item_delegate.h
@@ -22,12 +22,11 @@ class WindowWatcherShelfItemDelegate : public ShelfItemDelegate {
   ~WindowWatcherShelfItemDelegate() override;
 
   // ShelfItemDelegate:
-  ShelfAction ItemSelected(ui::EventType event_type,
-                           int event_flags,
-                           int64_t display_id,
-                           ShelfLaunchSource source) override;
-  ShelfAppMenuItemList GetAppMenuItems(int event_flags) override;
-  void ExecuteCommand(uint32_t command_id, int event_flags) override;
+  void ItemSelected(std::unique_ptr<ui::Event> event,
+                    int64_t display_id,
+                    ShelfLaunchSource source,
+                    const ItemSelectedCallback& callback) override;
+  void ExecuteCommand(uint32_t command_id, int32_t event_flags) override;
   void Close() override;
 
  private: