Merge branch 'material' into 'master'

widgetapp + material bug fix

See merge request upm-packages/ui-widgets/com.unity.uiwidgets!125

Runtime/material/theme.cs

                 return inheritedTheme.theme.data;
             }
 
-            //MaterialLocalizations localizations = MaterialLocalizations.of(context);
+            MaterialLocalizations localizations = MaterialLocalizations.of(context);
             ScriptCategory category = ScriptCategory.englishLike;
             ThemeData theme = inheritedTheme?.theme?.data ?? _kFallbackTheme;
             return ThemeData.localize(theme, theme.typography.geometryThemeFor(category));

Runtime/widgets/localizations.cs

 
         public T resourcesFor<T>(Type type) {
             D.assert(type != null);
-            T resources = (T) this._typeToResources[type];
+            T resources = (T) this._typeToResources.getOrDefault(type);
             return resources;
         }