dart2js cleanup: remove unused imports and variables

pkg/compiler/lib/src/io/source_information.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.source_information;
 
 import '../common.dart';
 import '../elements/elements.dart' show AstElement, LocalElement;
-import '../tree/tree.dart' show Node, Send;
 import '../js/js.dart' show JavaScriptNodeSourceInformation;
+import '../tree/tree.dart' show Node;
 import 'source_file.dart';
 
 /// Interface for passing source information, for instance for use in source
 /// maps, through the backend.
 abstract class SourceInformation extends JavaScriptNodeSourceInformation {
   const SourceInformation();
 
   SourceSpan get sourceSpan;
 
   /// The source location associated with the start of the JS node.
@@ skipping 215 matching lines @@
     return '${computeElementNameForSourceMaps(local.executableContext)}.$name';
   } else if (element.enclosingClass != null) {
     if (element.enclosingClass.isClosure) {
       return computeElementNameForSourceMaps(element.enclosingClass);
     }
     return '${element.enclosingClass.name}.${element.name}';
   } else {
     return element.name;
   }
 }