pkg/compiler: fix imports

pkg/compiler/lib/src/elements/common.dart

 // Copyright (c) 2015, 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.
 
 /// Mixins that implement convenience methods on [Element] subclasses.
 
 library elements.common;
 
 import '../common/names.dart' show Identifiers, Names, Uris;
 import '../core_types.dart' show CoreClasses;
 import '../dart_types.dart' show DartType, InterfaceType, FunctionType;
 import '../util/util.dart' show Link;
-
 import 'elements.dart';
 
 abstract class ElementCommon implements Element {
   @override
   bool get isLibrary => kind == ElementKind.LIBRARY;
 
   @override
   bool get isCompilationUnit => kind == ElementKind.COMPILATION_UNIT;
 
   @override
@@ skipping 622 matching lines @@
   @override
   bool get isBoolFromEnvironmentConstructor {
     return fromEnvironmentState == _FromEnvironmentState.BOOL;
   }
 
   @override
   bool get isStringFromEnvironmentConstructor {
     return fromEnvironmentState == _FromEnvironmentState.STRING;
   }
 }