fix shrine demo

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine/expanding_bottom_sheet.cs

   
   void _updateLists() {
     _internalList = ScopedModel<AppStateModel>.of(context).productsInCart.Keys.ToList();
-     HashSet<int> internalSet = new HashSet<int>(_internalList);
+    HashSet<int> internalSet = new HashSet<int>(_internalList);
-    HashSet<int> difference = null;
+    HashSet<int> difference = new HashSet<int>();
     foreach (var _set in internalSet)
     {
       if (!listSet.Contains(_set))

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine/model/product.cs

         public readonly string name;
         public readonly int price;
 
-        public string assetName => $"{this.id}-0.jpg";
+        public string assetName => $"shrine_images/{this.id}-0.jpg";
         public string assetPackage => "shrine_images";
 
 

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine/model/scoped_model.cs

 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 using Unity.UIWidgets.widgets;
+using UnityEngine;
 
 namespace UIWidgetsGallery.demo.shrine.model
 {
             Type type = typeof(_InheritedModel<T>);
 
             Widget widget = rebuildOnChange
-                ? context.inheritFromWidgetOfExactType(type)
-                : context.ancestorWidgetOfExactType(type);
+            ? context.dependOnInheritedWidgetOfExactType<_InheritedModel<T>>()
+            : context.findAncestorWidgetOfExactType<_InheritedModel<T>>();
 
             if (widget == null) {
                 throw new ScopedModelError();
 
     public class ScopedModelError : UIWidgetsError
     {
-        public ScopedModelError() : base("")
+        public ScopedModelError() : base("ScopedModelError")
         {
         }
 

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine/supplemental/asymmetric_view.cs

 
         int _oddCasesIndex(int input) {
             D.assert(input > 0);
-            return (input / 2) * 3 - 1;
+            
+            return ((input + 1) / 2) * 3 - 1;
-            : (totalItems / 3) * 2 - 1;
+            : ((totalItems + 2) / 3) * 2 - 1;
         }
 
   

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine/supplemental/product_card.cs

             
             ThemeData theme = Theme.of(context);
 
-            Image imageWidget = Image.asset(
+            Image imageWidget = Image.file(
-                package: product.assetPackage,
                 fit: BoxFit.cover
             );
 

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/gallery/demos.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
+using UIWidgetsGallery.demo;
 using UIWidgetsGallery.demo.material;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.widgets;
         {
             List<GalleryDemo> galleryDemos = new List<GalleryDemo>
             {
+                new GalleryDemo(
+                    title: "Shrine",
+                    subtitle: "Basic shopping app",
+                    icon: GalleryIcons.shrine,
+                    category: GalleryDemoCategory._kDemos,
+                    routeName: ShrineDemo.routeName,
+                    buildRoute: (BuildContext context) => new ShrineDemo()
+                ),
                 new GalleryDemo(
                     title: "Backdrop",
                     subtitle: $"Select a front layer from back layer",

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine_demo.cs

+using System;
+using UIWidgetsGallery.demo.shrine;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.widgets;
+
+namespace UIWidgetsGallery.demo
+{
+    class ShrineDemo : StatelessWidget {
+    public ShrineDemo(Key key = null) : base(key: key){}
+
+    public static readonly string routeName = "/shrine"; // Used by the Gallery app.
+
+    public override Widget build(BuildContext context) => new ShrineApp();
+    }
+}

Samples/UIWidgetsSamples_2019_4/Assets/UIWidgetsGallery/demo/shrine_demo.cs.meta

+fileFormatVersion: 2
+guid: b5da65292c17429ba697ebdefb05c8e4
+timeCreated: 1612512022