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

tests/corelib/map_test.dart

Index: tests/corelib/map_test.dart
diff --git a/tests/corelib/map_test.dart b/tests/corelib/map_test.dart
index 7e9d50db7707428403e4492518360a2ad988bc9f..a6db042d42f5ad92b8ba8b434c915b531496c5a6 100644
--- a/tests/corelib/map_test.dart
+++ b/tests/corelib/map_test.dart
@@ -29,12 +29,12 @@ void main() {
   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>());
@@ -45,8 +45,13 @@ void main() {
   // 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));
@@ -59,7 +64,7 @@ void main() {
                                                     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,
@@ -67,14 +72,14 @@ void main() {
   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,