[Web Payments] Add a mechanism to build item lists in the PR dialog.

chrome/browser/ui/views/payments/payment_request_item_list.cc

+// Copyright 2017 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 "chrome/browser/ui/views/payments/payment_request_item_list.h"
+
+#include "chrome/browser/ui/views/payments/payment_request_views_util.h"
+#include "ui/views/layout/box_layout.h"
+#include "ui/views/view.h"
+
+namespace payments {
+
+PaymentRequestItemList::Item::Item() {}
+
+PaymentRequestItemList::Item::~Item() {}
+
+views::View* PaymentRequestItemList::Item::GetItemView() {
+  if (!item_view_) {
+    item_view_ = CreateItemView();
+    item_view_->set_owned_by_client();
+  }
+
+  return item_view_.get();
+}
+
+PaymentRequestItemList::PaymentRequestItemList() {}
+
+PaymentRequestItemList::~PaymentRequestItemList() {}
+
+void PaymentRequestItemList::AddItem(
+    std::unique_ptr<PaymentRequestItemList::Item> item) {
+  items_.push_back(std::move(item));
+}
+
+std::unique_ptr<views::View> PaymentRequestItemList::CreateListView() {
+  std::unique_ptr<views::View> content_view = base::MakeUnique<views::View>();
+
+  views::BoxLayout* layout = new views::BoxLayout(
+      views::BoxLayout::kVertical, 0, kPaymentRequestRowVerticalInsets, 0);
+  content_view->SetLayoutManager(layout);
+
+  for (auto& item : items_) {
+    content_view->AddChildView(item->GetItemView());
+  }
+
+  return content_view;
+}
+
+}  // namespace payments