Adding isNotEmpty property to collection and string.

sdk/lib/html/html_common/css_class_set.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of html_common;
 
 abstract class CssClassSetImpl implements CssClassSet {
 
   String toString() {
     return readClasses().join(' ');
@@ skipping 38 matching lines @@
   Iterable<String> where(bool f(String element)) => readClasses().where(f);
 
   Iterable expand(Iterable f(String element)) => readClasses().expand(f);
 
   bool every(bool f(String element)) => readClasses().every(f);
 
   bool any(bool f(String element)) => readClasses().any(f);
 
   bool get isEmpty => readClasses().isEmpty;
 
+  bool get isNotEmpty => readClasses().isNotEmpty;
+
   int get length => readClasses().length;
 
   String reduce(String combine(String value, String element)) {
     return readClasses().reduce(combine);
   }
 
   dynamic fold(dynamic initialValue,
       dynamic combine(dynamic previousValue, String element)) {
     return readClasses().fold(initialValue, combine);
   }
@@ skipping 138 matching lines @@
    */
   Set<String> readClasses();
 
   /**
    * Join all the elements of a set into one string and write
    * back to the element.
    * This is intended to be overridden by specific implementations.
    */
   void writeClasses(Set<String> s);
 }