Add type annotations to some dart:html closures

tools/dom/src/CssClassSet.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;
 
 /** A Set that stores the CSS class names for an element. */
 abstract class CssClassSet implements Set<String> {
 
   /**
@@ skipping 78 matching lines @@
   final Iterable<Element> _elementIterable;
   Iterable<_ElementCssClassSet> _elementCssClassSetIterable;
 
   _MultiElementCssClassSet(this._elementIterable) {
     _elementCssClassSetIterable = new List.from(_elementIterable).map(
         (e) => new _ElementCssClassSet(e));
   }
 
   Set<String> readClasses() {
     var s = new LinkedHashSet<String>();
-    _elementCssClassSetIterable.forEach((e) => s.addAll(e.readClasses()));
+    _elementCssClassSetIterable.forEach(
+        (_ElementCssClassSet e) => s.addAll(e.readClasses()));
     return s;
   }
 
   void writeClasses(Set<String> s) {
-    var classes = new List.from(s).join(' ');
+    var classes = s.join(' ');
     for (Element e in _elementIterable) {
       e.className = classes;
     }
   }
 
   /**
    * Helper method used to modify the set of css classes on this element.
    *
    *   f - callback with:
    *   s - a Set of all the css class name currently on this element.
    *
    *   After f returns, the modified set is written to the
    *       className property of this element.
    */
   modify( f(Set<String> s)) {
-    _elementCssClassSetIterable.forEach((e) => e.modify(f));
+    _elementCssClassSetIterable.forEach((_ElementCssClassSet e) => e.modify(f));
   }
 
   /**
    * Adds the class [value] to the element if it is not on it, removes it if it
    * is.
    */
   bool toggle(String value, [bool shouldAdd]) =>
-      _modifyWithReturnValue((e) => e.toggle(value, shouldAdd));
+      _elementCssClassSetIterable.fold(false,
+          (bool changed, _ElementCssClassSet e) =>
+              e.toggle(value, shouldAdd) || changed);
 
   /**
    * Remove the class [value] from element, and return true on successful
    * removal.
    *
    * This is the Dart equivalent of jQuery's
    * [removeClass](http://api.jquery.com/removeClass/).
    */
-  bool remove(Object value) => _modifyWithReturnValue((e) => e.remove(value));
-
-  bool _modifyWithReturnValue(f) => _elementCssClassSetIterable.fold(
-      false, (prevValue, element) => f(element) || prevValue);
+  bool remove(Object value) => _elementCssClassSetIterable.fold(false,
+      (bool changed, _ElementCssClassSet e) => e.remove(value) || changed);
 }
 
 class _ElementCssClassSet extends CssClassSetImpl {
 
   final Element _element;
 
   _ElementCssClassSet(this._element);
 
   Set<String> readClasses() {
     var s = new LinkedHashSet<String>();
     var classname = _element.className;
 
     for (String name in classname.split(' ')) {
       String trimmed = name.trim();
       if (!trimmed.isEmpty) {
         s.add(trimmed);
       }
     }
     return s;
   }
 
   void writeClasses(Set<String> s) {
-    List list = new List.from(s);
     _element.className = s.join(' ');
   }
 }