Fix hints reported by analyzer.

pkg/compiler/lib/src/resolution/variables.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.
 
 library dart2js.resolution.variables;
 
 import '../common.dart';
 import '../common/resolution.dart';
 import '../elements/modelx.dart' show LocalVariableElementX, VariableList;
 import '../tree/tree.dart';
-import '../universe/use.dart' show TypeUse;
 import '../universe/feature.dart';
 import '../util/util.dart' show Link;
 import 'members.dart' show ResolverVisitor;
 import 'registry.dart' show ResolutionRegistry;
 import 'resolution_common.dart' show CommonResolverVisitor;
 import 'scope.dart' show VariableDefinitionScope;
 
 class VariableDefinitionsVisitor extends CommonResolverVisitor<Identifier> {
   VariableDefinitions definitions;
   ResolverVisitor resolver;
@@ skipping 47 matching lines @@
       resolver.addToScope(element);
       if (definitions.modifiers.isConst) {
         addDeferredAction(element, () {
           element.constant =
               resolution.resolver.constantCompiler.compileConstant(element);
         });
       }
     }
   }
 }