Revert "Remove dart2js specific core.dart and coreimpl.dart files."

lib/compiler/implementation/lib/core.dart

Index: lib/compiler/implementation/lib/core.dart
diff --git a/lib/compiler/implementation/lib/core.dart b/lib/compiler/implementation/lib/core.dart
new file mode 100644
index 0000000000000000000000000000000000000000..218692a7cdbc5244732276c8ebd38a55476eee81
--- /dev/null
+++ b/lib/compiler/implementation/lib/core.dart
@@ -0,0 +1,43 @@
+// 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('dart:core');
+
+#import('dart:math');
+
+#import('coreimpl.dart');
+
+#import('js_helper.dart'); // TODO(ahe): remove this import.
+
+#source('../../../../lib/core/bool.dart');
+#source('../../../../lib/core/collection.dart');
+#source('../../../../lib/core/comparable.dart');
+#source('../../../../lib/core/date.dart');
+#source('../../../../lib/core/double.dart');
+#source('../../../../lib/core/duration.dart');
+#source('../../../../lib/core/errors.dart');
+#source('../../../../lib/core/exceptions.dart');
+#source('../../../../lib/core/expando.dart');
+#source('../../../../lib/core/expect.dart');
+#source('../../../../lib/core/function.dart');
+#source('../../../../lib/core/future.dart');
+#source('../../../../lib/core/hashable.dart');
+#source('../../../../lib/core/int.dart');
+#source('../../../../lib/core/iterable.dart');
+#source('../../../../lib/core/iterator.dart');
+#source('../../../../lib/core/list.dart');
+#source('../../../../lib/core/map.dart');
+#source('../../../../lib/core/num.dart');
+#source('../../../../lib/core/object.dart');
+#source('../../../../lib/core/options.dart');
+#source('../../../../lib/core/print.dart');
+#source('../../../../lib/core/pattern.dart');
+#source('../../../../lib/core/queue.dart');
+#source('../../../../lib/core/regexp.dart');
+#source('../../../../lib/core/set.dart');
+#source('../../../../lib/core/stopwatch.dart');
+#source('../../../../lib/core/string.dart');
+#source('../../../../lib/core/string_buffer.dart');
+#source('../../../../lib/core/strings.dart');
+#source('mock.dart');