Make LinkedHashMap also have a factory constructor and be customizable

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 15 matching lines @@
   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 LinkedHashMap());
   testNumericKeys(new LinkedHashMap<num, String>());
+  testNumericKeys(new LinkedHashMap(equals: identical));
+  testNumericKeys(new LinkedHashMap<num, String>(equals: identical));
 
   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));
 
   testCustomMap(new HashMap(equals: myEquals, hashCode: myHashCode));
+  testCustomMap(new LinkedHashMap(equals: myEquals, hashCode: myHashCode));
 
   testIterationOrder(new LinkedHashMap());
+  testIterationOrder(new LinkedHashMap(equals: identical));
 }
 
 
 void test(Map map) {
   testDeletedElement(map);
   testMap(map, 1, 2, 3, 4, 5, 6, 7, 8);
   map.clear();
   testMap(map, "value1", "value2", "value3", "value4", "value5",
           "value6", "value7", "value8");
 }
@@ skipping 580 matching lines @@
 
 int myHashCode(Customer c) => c.secondId;
 bool myEquals(Customer a, Customer b) => a.secondId == b.secondId;
 
 testIterationOrder(Map map) {
   var order = [0, 6, 4, 2, 7, 9, 7, 1, 2, 5, 3];
   for (int i = 0; i < order.length; i++) map[order[i]] = i;
   Expect.listEquals(map.keys.toList(), [0, 6, 4, 2, 7, 9, 1, 5, 3]);
   Expect.listEquals(map.values.toList(), [0, 1, 2, 8, 6, 5, 7, 9, 10]);
 }