Fix issue.

Runtime/material/app.cs

             this.title = title;
             this.color = color;
             this.theme = theme;
-            this.dartTheme = darkTheme;
+            this.darkTheme = darkTheme;
             this.locale = locale;
             this.localizationsDelegates = localizationsDelegates;
             this.localeListResolutionCallback = localeListResolutionCallback;
 
         public readonly ThemeData theme;
 
-        public readonly ThemeData dartTheme;
+        public readonly ThemeData darkTheme;
 
         public readonly Color color;
 

Runtime/material/chip.cs

             Color selectedShadowColor = null,
             ShapeBorder avatarBorder = null
         ) : base(key: key) {
-            D.assert(selected != null);
-            D.assert(isEnabled != null);
-            D.assert(clipBehavior != null);
             D.assert(pressElevation == null || pressElevation >= 0.0f);
             D.assert(elevation == null || elevation >= 0.0f);
             this._avatarBorder = avatarBorder ?? new CircleBorder();
 
         float? _elevation;
 
-        public Color selectedShadowColor {
-            get { return this._selectedShadowColor; }
-        }
-
-        Color _selectedShadowColor;
-
         public ShapeBorder avatarBorder {
             get { return this._avatarBorder; }
         }
         ) : base(key: key) {
             D.assert(selected != null);
             D.assert(label != null);
-            D.assert(clipBehavior != null);
             D.assert(pressElevation == null || pressElevation >= 0.0f);
             D.assert(elevation == null || elevation >= 0.0f);
             this._avatarBorder = avatarBorder ?? new CircleBorder();

Runtime/material/chip_theme.cs

         }
 
         public static ChipThemeData lerp(ChipThemeData a, ChipThemeData b, float t) {
-            D.assert(t != null);
             if (a == null && b == null) {
                 return null;
             }