update Map

tool/input_sdk/patch/core_patch.dart

Index: tool/input_sdk/patch/core_patch.dart
diff --git a/tool/input_sdk/patch/core_patch.dart b/tool/input_sdk/patch/core_patch.dart
index 94b58883b57e997a7ab8cc0e627a8d9ac6c8c680..fdef106e706229b3cf260f346f680a1886883637 100644
--- a/tool/input_sdk/patch/core_patch.dart
+++ b/tool/input_sdk/patch/core_patch.dart
@@ -7,8 +7,10 @@ import "dart:_internal" as _symbol_dev;
 import 'dart:_interceptors';
 import 'dart:_js_helper' show patch,
                               checkInt,
+                              ConstantMap,
                               getRuntimeType,
                               jsonEncodeNative,
+                              JsLinkedHashMap,
                               JSSyntaxRegExp,
                               Primitives,
                               stringJoinUnchecked,
@@ -331,9 +333,7 @@ class List<E> {
 @patch
 class Map<K, V> {
   @patch
-  factory Map.unmodifiable(Map other) {
-    return new UnmodifiableMapView<K, V>(new Map<K, V>.from(other));

[sra1, 2016/05/09 23:16:40]

I think it is OK to leave this as-is.

The various ConstantMaps are not necessarily a good fit for DDC - it still needs
work on what a const map literal really is.

[Harry Terkelsen, 2016/05/10 00:59:27]

Done.

-  }
+  factory Map.unmodifiable(Map other) = ConstantMap<K, V>.from;
 
   @patch
   factory Map() = JsLinkedHashMap<K, V>.es6;