Update implementations to use Object.identityHashCode for identity map/set

tests/corelib/map_test.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.
 
 library map_test;
 import "package:expect/expect.dart";
 import 'dart:collection';
 
 void main() {
   test(new HashMap());
@@ skipping 11 matching lines @@
   testWeirdStringKeys(new HashMap<String, String>());
   testWeirdStringKeys(new LinkedHashMap());
   testWeirdStringKeys(new LinkedHashMap<String, String>());
   testWeirdStringKeys(new SplayTreeMap());
   testWeirdStringKeys(new SplayTreeMap<String, String>());
 
   testNumericKeys(new Map());
   testNumericKeys(new Map<num, String>());
   testNumericKeys(new HashMap());
   testNumericKeys(new HashMap<num, String>());
-  testNumericKeys(new HashMap(equals: identical));
-  testNumericKeys(new HashMap<num, String>(equals: identical));
+  testNumericKeys(new HashMap.identity());
+  testNumericKeys(new HashMap<num, String>.identity());
   testNumericKeys(new LinkedHashMap());
   testNumericKeys(new LinkedHashMap<num, String>());
-  testNumericKeys(new LinkedHashMap(equals: identical));
-  testNumericKeys(new LinkedHashMap<num, String>(equals: identical));
+  testNumericKeys(new LinkedHashMap.identity());
+  testNumericKeys(new LinkedHashMap<num, String>.identity());
 
   testNaNKeys(new Map());
   testNaNKeys(new Map<num, String>());
   testNaNKeys(new HashMap());
   testNaNKeys(new HashMap<num, String>());
   testNaNKeys(new LinkedHashMap());
   testNaNKeys(new LinkedHashMap<num, String>());
   // Identity maps fail the NaN-keys tests because the test assumes that
   // NaN is not equal to NaN.
 
-  testIdentityMap(new HashMap(equals: identical));
-  testIdentityMap(new LinkedHashMap(equals: identical));
+  testIdentityMap(new Map.identity());
+  testIdentityMap(new HashMap.identity());
+  testIdentityMap(new LinkedHashMap.identity());
+  testIdentityMap(new HashMap(equals: identical,
+                              hashCode: Object.identityHashCode));
+  testIdentityMap(new LinkedHashMap(equals: identical,
+                                    hashCode: Object.identityHashCode));
 
   testCustomMap(new HashMap(equals: myEquals, hashCode: myHashCode,
                             isValidKey: (v) => v is Customer));
   testCustomMap(new LinkedHashMap(equals: myEquals, hashCode: myHashCode,
                                   isValidKey: (v) => v is Customer));
   testCustomMap(new HashMap<Customer,dynamic>(equals: myEquals,
                                               hashCode: myHashCode));
 
   testCustomMap(new LinkedHashMap<Customer,dynamic>(equals: myEquals,
                                                     hashCode: myHashCode));
 
   testIterationOrder(new LinkedHashMap());
-  testIterationOrder(new LinkedHashMap(equals: identical));
+  testIterationOrder(new LinkedHashMap.identity());
 
   testOtherKeys(new SplayTreeMap<int, int>());
   testOtherKeys(new SplayTreeMap<int, int>((int a, int b) => a - b,
                                            (v) => v is int));
   testOtherKeys(new SplayTreeMap((int a, int b) => a - b,
                                  (v) => v is int));
   testOtherKeys(new HashMap<int, int>());
-  testOtherKeys(new HashMap<int, int>(equals: identical));
+  testOtherKeys(new HashMap<int, int>.identity());
   testOtherKeys(new HashMap<int, int>(hashCode: (v) => v.hashCode,
                                       isValidKey: (v) => v is int));
   testOtherKeys(new HashMap(equals: (int x, int y) => x == y,
                             hashCode: (int v) => v.hashCode,
                             isValidKey: (v) => v is int));
   testOtherKeys(new LinkedHashMap<int, int>());
-  testOtherKeys(new LinkedHashMap<int, int>(equals: identical));
+  testOtherKeys(new LinkedHashMap<int, int>.identity());
   testOtherKeys(new LinkedHashMap<int, int>(hashCode: (v) => v.hashCode,
                                        isValidKey: (v) => v is int));
   testOtherKeys(new LinkedHashMap(equals: (int x, int y) => x == y,
                                   hashCode: (int v) => v.hashCode,
                                   isValidKey: (v) => v is int));
 }
 
 
 void test(Map map) {
   testDeletedElement(map);
@@ skipping 618 matching lines @@
   map[0] = 0;
   map[1] = 1;
   map[2] = 2;
   Expect.isFalse(map.containsKey("not an int"));
   Expect.isFalse(map.containsKey(1.5));
   Expect.isNull(map.remove("not an int"));
   Expect.isNull(map.remove(1.5));
   Expect.isNull(map["not an int"]);
   Expect.isNull(map[1.5]);
 }