Add YamlMap.addAll.

BUG=13356
R=jmesserly@google.com

Review URL: https://codereview.chromium.org//24175008

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/yaml@27725 260f80e4-7a28-3924-810f-c04153c831b5

pkgs/yaml/lib/src/yaml_map.dart

diff --git a/pkgs/yaml/lib/src/yaml_map.dart b/pkgs/yaml/lib/src/yaml_map.dart
index aa8397c..50ae2d9 100644
--- a/pkgs/yaml/lib/src/yaml_map.dart
+++ b/pkgs/yaml/lib/src/yaml_map.dart
@@ -23,6 +23,12 @@
 
   YamlMap._wrap(this._map);
 
+  void addAll(Map other) {
+    other.forEach((key, value) {
+      this[key] = value;
+    });
+  }
+
   bool containsValue(value) => _map.containsValue(value);
   bool containsKey(key) => _map.containsKey(_wrapKey(key));
   operator [](key) => _map[_wrapKey(key)];