update elements and fix some bugs

lib/iron_list.dart

 // DO NOT EDIT: auto-generated with `pub run custom_element_apigen:update`
 
 /// Dart API for the polymer element `iron_list`.
 @HtmlImport('iron_list_nodart.html')
 library polymer_elements.lib.src.iron_list.iron_list;
 
 import 'dart:html';
 import 'dart:js' show JsArray, JsObject;
 import 'package:web_components/web_components.dart';
 import 'package:polymer_interop/polymer_interop.dart';
@@ skipping 48 matching lines @@
 ///       <iron-ajax url="data.json" last-response="{{data}}" auto></iron-ajax>
 ///       <iron-list items="[[data]]" as="item">
 ///         <template>
 ///           <div>
 ///             Name: <span>[[item.name]]</span>
 ///           </div>
 ///         </template>
 ///       </iron-list>
 ///     </template>
 ///
+/// ### Styling
+///
+/// Use the `--iron-list-items-container` mixin to style the container of items, e.g.
+///
+///     iron-list {
+///      --iron-list-items-container: {
+///         margin: auto;
+///       };
+///     }
+///
 /// ### Resizing
 ///
-/// `iron-list` lays out the items when it recives a notification via the `resize` event.
+/// `iron-list` lays out the items when it recives a notification via the `iron-resize` event.
 /// This event is fired by any element that implements `IronResizableBehavior`.
 ///
 /// By default, elements such as `iron-pages`, `paper-tabs` or `paper-dialog` will trigger
 /// this event automatically. If you hide the list manually (e.g. you use `display: none`)
 /// you might want to implement `IronResizableBehavior` or fire this event manually right
 /// after the list became visible again. e.g.
 ///
-///     document.querySelector('iron-list').fire('resize');
+///     document.querySelector('iron-list').fire('iron-resize');
 @CustomElementProxy('iron-list')
 class IronList extends HtmlElement with CustomElementProxyMixin, PolymerBase, Templatizer, IronResizableBehavior {
   IronList.created() : super.created();
   factory IronList() => new Element.tag('iron-list');
 
   /// The name of the variable to add to the binding scope for the array
   /// element associated with a given template instance.
   String get as => jsElement[r'as'];
   set as(String value) { jsElement[r'as'] = value; }
 
-  /// Gets the first visible item in the viewport.
-  get firstVisibleIndex => jsElement[r'firstVisibleIndex'];
+  /// Gets the index of the first visible item in the viewport.
+  num get firstVisibleIndex => jsElement[r'firstVisibleIndex'];
+  set firstVisibleIndex(num value) { jsElement[r'firstVisibleIndex'] = value; }
 
   /// The name of the variable to add to the binding scope with the index
-  /// for the row.  If `sort` is provided, the index will reflect the
-  /// sorted order (rather than the original array order).
+  /// for the row.
   String get indexAs => jsElement[r'indexAs'];
   set indexAs(String value) { jsElement[r'indexAs'] = value; }
 
   /// An array containing items determining how many instances of the template
   /// to stamp and that that each template instance should bind to.
   List get items => jsElement[r'items'];
   set items(List value) { jsElement[r'items'] = (value != null && value is! JsArray) ? new JsObject.jsify(value) : value;}
 
   /// When `true`, multiple items may be selected at once (in this case,
   /// `selected` is an array of currently selected items).  When `false`,
@@ skipping 21 matching lines @@
   /// Note that tapping focusable elements within the list item will not
   /// result in selection, since they are presumed to have their * own action.
   bool get selectionEnabled => jsElement[r'selectionEnabled'];
   set selectionEnabled(bool value) { jsElement[r'selectionEnabled'] = value; }
 
   /// Clears the current selection state of the list.
   clearSelection() =>
       jsElement.callMethod('clearSelection', []);
 
   /// Deselects the given item list if it is already selected.
-  /// [item]: the item object or its index
+  /// [item]: The item object or its index
   deselectItem(item) =>
       jsElement.callMethod('deselectItem', [item]);
 
   /// Scroll to a specific item in the virtual list regardless
   /// of the physical items in the DOM tree.
   /// [idx]: The index of the item
   scrollToIndex(num idx) =>
       jsElement.callMethod('scrollToIndex', [idx]);
 
   /// Select the list item at the given index.
-  /// [item]: the item object or its index
+  /// [item]: The item object or its index
   selectItem(item) =>
       jsElement.callMethod('selectItem', [item]);
 
   /// Select or deselect a given item depending on whether the item
   /// has already been selected.
-  /// [item]: the item object or its index
+  /// [item]: The item object or its index
   toggleSelectionForItem(item) =>
       jsElement.callMethod('toggleSelectionForItem', [item]);
 
+  /// Updates the size of an item.
+  /// [item]: The item object or its index
+  updateSizeForItem(item) =>
+      jsElement.callMethod('updateSizeForItem', [item]);
+
   /// Invoke this method if you dynamically update the viewport's
   /// size or CSS padding.
   updateViewportBoundaries() =>
       jsElement.callMethod('updateViewportBoundaries', []);
 }