update Map

tool/input_sdk/patch/core_patch.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.
 
 // Patch file for dart:core classes.
 import "dart:_internal" as _symbol_dev;
 import 'dart:_interceptors';
 import 'dart:_js_helper' show patch,
                               checkInt,
+                              ConstantMap,
                               getRuntimeType,
                               jsonEncodeNative,
+                              JsLinkedHashMap,
                               JSSyntaxRegExp,
                               Primitives,
                               stringJoinUnchecked,
                               objectHashCode,
                               getTraceFromException;
 
 import 'dart:_foreign_helper' show JS;
 
 import 'dart:_native_typed_data' show NativeUint8List;
 
@@ skipping 302 matching lines @@
   @patch
   factory List.unmodifiable(Iterable elements) {
     var result = new List<E>.from(elements, growable: false);
     return makeFixedListUnmodifiable/*<E>*/(result);
   }
 }
 
 @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;
 }
 
 @patch
 class String {
   @patch
   factory String.fromCharCodes(Iterable<int> charCodes,
                                [int start = 0, int end]) {
@@ skipping 222 matching lines @@
       return getTraceFromException(error);
     }
     // Fallback if Error.captureStackTrace does not exist.
     try {
       throw '';
     } catch (_, stackTrace) {
       return stackTrace;
     }
   }
 }