Use common.dart to re-export commonly used entities.

pkg/compiler/lib/src/resolution/enum_creator.dart

 // Copyright (c) 2014, 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 dart2js.resolution.enum_creator;
 
+import '../common.dart';
 import '../core_types.dart' show
     CoreTypes;
 import '../dart_types.dart';
-import '../diagnostics/diagnostic_listener.dart' show
-    DiagnosticReporter;
 import '../elements/elements.dart';
 import '../elements/modelx.dart';
 import '../tokens/keyword.dart' show
     Keyword;
 import '../tokens/precedence.dart';
 import '../tokens/precedence_constants.dart' as Precedence;
 import '../tokens/token.dart';
 import '../tree/tree.dart';
 import '../util/util.dart';
 
@@ skipping 281 matching lines @@
     EnumMethodElementX toString = new EnumMethodElementX('toString',
         enumClass, Modifiers.EMPTY, toStringNode);
     FunctionSignatureX toStringSignature = new FunctionSignatureX(
         type: new FunctionType(toString, stringType));
     toString.functionSignature = toStringSignature;
     enumClass.addMember(toString, reporter);
 
     enumClass.enumValues = enumValues;
   }
 }