mash: Fix ShelfItem mojo struct; add enums and traits.

ash/common/shelf/shelf_controller.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/shelf/shelf_controller.h"
 
 #include "ash/common/shelf/app_list_shelf_item_delegate.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
@@ skipping 94 matching lines @@
                                           int64_t display_id) {
   WmShelf* shelf = GetShelfForDisplay(display_id);
   // TODO(jamescook): The initialization check should not be necessary, but
   // otherwise this wrongly tries to set auto-hide state on a secondary display
   // during login before the ShelfView is created.
   if (shelf && shelf->IsShelfInitialized())
     shelf->SetAutoHideBehavior(auto_hide);
 }
 
 void ShelfController::PinItem(
-    mojom::ShelfItemPtr item,
+    const ShelfItem& item,
     mojom::ShelfItemDelegateAssociatedPtrInfo delegate) {
   NOTIMPLEMENTED();
 }
 
 void ShelfController::UnpinItem(const std::string& app_id) {
   NOTIMPLEMENTED();
 }
 
 void ShelfController::SetItemImage(const std::string& app_id,
                                    const SkBitmap& image) {
   if (!app_id_to_shelf_id_.count(app_id))
     return;
   ShelfID shelf_id = app_id_to_shelf_id_[app_id];
   int index = model_.ItemIndexByID(shelf_id);
   DCHECK_GE(index, 0);
   ShelfItem item = *model_.ItemByID(shelf_id);
   item.image = GetShelfIconFromBitmap(image);
   model_.Set(index, item);
 }
 
 }  // namespace ash