Support map in generated dart:html files.

client/html/generated/src/wrapping/_MediaListWrappingImplementation.dart

 // Copyright (c) 2011, 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.
 
 // WARNING: Do not edit - generated code.
 
 class MediaListWrappingImplementation extends DOMWrapperBase implements MediaList {
   MediaListWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
   int get length() { return _ptr.length; }
@@ skipping 48 matching lines @@
   }
 
   String last() {
     return this[length - 1];
   }
 
   void forEach(void f(String element)) {
     _Collections.forEach(this, f);
   }
 
+  Collection map(f(String element)) {
+    return _Collections.map(this, [], f);
+  }
+
   Collection<String> filter(bool f(String element)) {
     return _Collections.filter(this, new List<String>(), f);
   }
 
   bool every(bool f(String element)) {
     return _Collections.every(this, f);
   }
 
   bool some(bool f(String element)) {
     return _Collections.some(this, f);
@@ skipping 30 matching lines @@
 
   void deleteMedium(String oldMedium) {
     _ptr.deleteMedium(oldMedium);
     return;
   }
 
   String item(int index) {
     return _ptr.item(index);
   }
 }