dart2js cleanup: remove unused imports and variables

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

 // 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 dart2js.common.resolution;
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/expressions.dart' show ConstantExpression;
 import '../core_types.dart' show CoreTypes;
 import '../dart_types.dart' show DartType, InterfaceType;
 import '../elements/elements.dart'
     show
         AstElement,
         ClassElement,
         Element,
-        ErroneousElement,
         FunctionElement,
         FunctionSignature,
-        LocalFunctionElement,
         MetadataAnnotation,
-        MethodElement,
         ResolvedAst,
-        TypedefElement,
-        TypeVariableElement;
+        TypedefElement;
 import '../enqueue.dart' show ResolutionEnqueuer;
 import '../options.dart' show ParserOptions;
 import '../parser/element_listener.dart' show ScannerOptions;
-import '../tree/tree.dart' show AsyncForIn, Send, TypeAnnotation;
+import '../tree/tree.dart' show TypeAnnotation;
 import '../universe/world_impact.dart' show WorldImpact;
 import 'work.dart' show ItemCompilationContext, WorkItem;
 
 /// [WorkItem] used exclusively by the [ResolutionEnqueuer].
 class ResolutionWorkItem extends WorkItem {
   bool _isAnalyzed = false;
 
   ResolutionWorkItem(
       AstElement element, ItemCompilationContext compilationContext)
       : super(element, compilationContext);
@@ skipping 197 matching lines @@
 }
 
 // TODO(johnniwinther): Rename to `Parser` or `ParsingContext`.
 abstract class Parsing {
   DiagnosticReporter get reporter;
   void parsePatchClass(ClassElement cls);
   measure(f());
   ScannerOptions getScannerOptionsFor(Element element);
   ParserOptions get parserOptions;
 }