Fixes for a number of dart analyzer issues in dart:html.

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;
 
 abstract class CssClassSet implements Set<String> {
 
   String toString() {
     return Strings.join(new List.from(readClasses()), ' ');
@@ skipping 78 matching lines @@
 
   bool isSubsetOf(Collection<String> collection) =>
     readClasses().isSubsetOf(collection);
 
   bool containsAll(Collection<String> collection) =>
     readClasses().containsAll(collection);
 
   Set<String> intersection(Collection<String> other) =>
     readClasses().intersection(other);
 
+  String get first => readClasses().first;
+  String get last => readClasses().last;
+  String get single => readClasses().single;
+  List<String> toList() => readClasses().toList();
+  Set<String> toSet() => readClasses().toSet();
+  String min([int compare(String a, String b)]) =>
+      readClasses().min(compare);
+  String max([int compare(String a, String b)]) =>
+      readClasses().max(compare);
+  Iterable<String> take(int n) => readClasses().take(n);
+  Iterable<String> takeWhile(bool test(String value)) =>
+      readClasses().takeWhile(test);
+  Iterable<String> skip(int n) => readClasses().skip(n);
+  Iterable<String> skipWhile(bool test(String value)) =>
+      readClasses().skipWhile(test);
+  String firstMatching(bool test(String value), { String orElse() }) =>
+      readClasses().firstMatching(test, orElse: orElse);
+  String lastMatching(bool test(String value), {String orElse()}) =>
+      readClasses().lastMatching(test, orElse: orElse);
+  String singleMatching(bool test(String value)) =>
+      readClasses().singleMatching(test);
+  String elementAt(int index) => readClasses().elementAt(index);
+
   void clear() {
     _modify((s) => s.clear());
   }
   // interface Set - END
 
   /**
    * 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.
@@ skipping 14 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);
 }