Revert revision 33053

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.
+  * The `ngStyle` directive allows you to set CSS style on an HTML element conditionally.
   *
   * @example
-  *     <span ng-style="{color:'red'}">Sample Text</span>
+        <span ng-style="{color:'red'}">Sample Text</span>
   */
 @NgDirective(
     selector: '[ng-style]',
     map: const { 'ng-style': '@styleExpression'})
 class NgStyleDirective {
-  final dom.Element _element;
-  final Scope _scope;
-  final AstParser _parser;
+  dom.Element _element;
+  Scope _scope;
 
   String _styleExpression;
-  Watch _watch;
 
-  NgStyleDirective(this._element, this._scope, this._parser);
+  NgStyleDirective(this._element, this._scope);
+
+  Function _removeWatch = () => null;
+  var _lastStyles;
 
 /**
   * 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.
+  *      object whose keys are CSS style names and values are corresponding values for those CSS
+  *      keys.
   */
   set styleExpression(String value) {
     _styleExpression = value;
-    if (_watch != null) _watch.remove();
-    _watch = _scope.watch(_parser(_styleExpression, collection: true), _onStyleChange);
+    _removeWatch();
+    _removeWatch = _scope.$watchCollection(_styleExpression, _onStyleChange);
   }
 
-  _onStyleChange(MapChangeRecord mapChangeRecord, _) {
-    if (mapChangeRecord != null) {
-      dom.CssStyleDeclaration css = _element.style;
-      fn(MapKeyValue kv) => css.setProperty(kv.key, kv.currentValue == null ? '' : kv.currentValue);
+  _onStyleChange(Map newStyles) {
+    dom.CssStyleDeclaration css = _element.style;
+    if (_lastStyles != null) {
+      _lastStyles.forEach((val, style) { css.setProperty(val, ''); });
+    }
+    _lastStyles = newStyles;
 
-      mapChangeRecord
-        ..forEachRemoval(fn)
-        ..forEachChange(fn)
-        ..forEachAddition(fn);
+    if (newStyles != null) {
+      newStyles.forEach((val, style) { css.setProperty(val, style); });
     }
   }
 }