Fix bug 15417

tools/dom/templates/html/impl/impl_Storage.darttemplate

 // 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 $LIBRARYNAME;
 
 /**
  * The type used by the
  * [Window.localStorage] and [Window.sessionStorage] properties.
  * Storage is implemented as a Map<String, String>.
@@ skipping 14 matching lines @@
  *
  * For more examples of using this API, see
  * [localstorage_test.dart](http://code.google.com/p/dart/source/browse/branches/bleeding_edge/dart/tests/html/localstorage_test.dart).
  * For details on using the Map API, see the
  * [Maps](http://www.dartlang.org/docs/library-tour/#maps-aka-dictionaries-or-hashes)
  * section of the library tour.
  */
 $(ANNOTATIONS)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS
     implements Map<String, String> $NATIVESPEC {
 
+  void addAll(Map<String, String> other) {
+    other.forEach((k, v) { this[k] = v; });
+  }
+
   // TODO(nweiz): update this when maps support lazy iteration
   bool containsValue(String value) => values.any((e) => e == value);
 
   bool containsKey(String key) => _getItem(key) != null;
 
   String operator [](String key) => _getItem(key);
 
   void operator []=(String key, String value) { _setItem(key, value); }
 
   String putIfAbsent(String key, String ifAbsent()) {
@@ skipping 30 matching lines @@
     return values;
   }
 
   int get length => _length;
 
   bool get isEmpty => _key(0) == null;
 
   bool get isNotEmpty => !isEmpty;
 $!MEMBERS
 }