Updating Angular version

third_party/pkg/angular/lib/directive/ng_style.dart

 part of angular.directive;
 
 /**
   * The `ngStyle` directive allows you to set CSS style on an HTML element conditionally.
   *
   * @example
         <span ng-style="{color:'red'}">Sample Text</span>
   */
 @NgDirective(
     selector: '[ng-style]',
     map: const { 'ng-style': '@styleExpression'})
 class NgStyleDirective {
   dom.Element _element;
   Scope _scope;
 
   String _styleExpression;
 
   NgStyleDirective(this._element, this._scope);
 
   Function _removeWatch = () => null;
   var _lastStyles;
 
 /**
-  * ng-style attribute takes an expression hich evals to an
+  * ng-style attribute takes an expression which evaluates to an
   *      object whose keys are CSS style names and values are corresponding values for those CSS
   *      keys.
   */
   set styleExpression(String value) {
     _styleExpression = value;
     _removeWatch();
     _removeWatch = _scope.$watchCollection(_styleExpression, _onStyleChange);
   }
 
   _onStyleChange(Map newStyles) {
     dom.CssStyleDeclaration css = _element.style;
     if (_lastStyles != null) {
       _lastStyles.forEach((val, style) { css.setProperty(val, ''); });
     }
     _lastStyles = newStyles;
 
     if (newStyles != null) {
       newStyles.forEach((val, style) { css.setProperty(val, style); });
     }
   }
 }