mash: Move shelf model and item classes to ash/common/shelf

ash/shelf/shelf_item_types.cc

-// Copyright 2014 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/shelf/shelf_item_types.h"
-
-#include "ash/common/shelf/shelf_constants.h"
-
-namespace ash {
-
-ShelfItem::ShelfItem()
-    : type(TYPE_UNDEFINED),
-      id(kInvalidShelfID),
-      status(STATUS_CLOSED) {
-}
-
-ShelfItem::~ShelfItem() {
-}
-
-ShelfItemDetails::ShelfItemDetails()
-    : type(TYPE_UNDEFINED),
-      image_resource_id(kInvalidImageResourceID) {
-}
-
-ShelfItemDetails::~ShelfItemDetails() {
-}
-
-}  // namespace ash