Introduce "CommonElements"

tests/compiler/dart2js/compiler_helper.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.
 
 library compiler_helper;
 
 import 'dart:async';
 import "package:expect/expect.dart";
 
 import 'package:compiler/src/elements/elements.dart'
@@ skipping 195 matching lines @@
 }
 
 types.TypeMask findTypeMask(compiler, String name,
                             [String how = 'nonNullExact']) {
   var sourceName = name;
   var element = compiler.mainApp.find(sourceName);
   if (element == null) {
     element = compiler.backend.helpers.interceptorsLibrary.find(sourceName);
   }
   if (element == null) {
-    element = compiler.coreLibrary.find(sourceName);
+    element = compiler.commonElements.coreLibrary.find(sourceName);
   }
   Expect.isNotNull(element, 'Could not locate $name');
   switch (how) {
     case 'exact':
       return new types.TypeMask.exact(element, compiler.world);
     case 'nonNullExact':
       return new types.TypeMask.nonNullExact(element, compiler.world);
     case 'subclass':
       return new types.TypeMask.subclass(element, compiler.world);
     case 'nonNullSubclass':
@@ skipping 63 matching lines @@
     regexp = regexp.replaceAll(xRe, '(?:$anyIdentifier)');
     final spaceRe = new RegExp('\\s+');
     regexp = regexp.replaceAll(spaceRe, '(?:\\s*)');
     if (shouldMatch) {
       Expect.isTrue(new RegExp(regexp).hasMatch(generated));
     } else {
       Expect.isFalse(new RegExp(regexp).hasMatch(generated));
     }
   });
 }