Refactor DartTypeVisitor and ElementVisitor.

pkg/compiler/lib/src/closure.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 closureToClassMapper;
 
 import "elements/elements.dart";
 import "dart2jslib.dart";
 import "dart_types.dart";
 import "js_backend/js_backend.dart" show JavaScriptBackend;
@@ skipping 125 matching lines @@
   DartType get type {
     if (local is LocalElement) {
       LocalElement element = local;
       return element.type;
     }
     return const DynamicType();
   }
 
   String toString() => "ClosureFieldElement($name)";
 
-  accept(ElementVisitor visitor) => visitor.visitClosureFieldElement(this);
+  accept(ElementVisitor visitor, arg) {
+    return visitor.visitClosureFieldElement(this, arg);
+  }
 
   Element get analyzableElement => closureClass.methodElement.analyzableElement;
 
   @override
   List<FunctionElement> get nestedClosures => const <FunctionElement>[];
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to find
 // a more general solution.
 class ClosureClassElement extends ClassElementX {
@@ skipping 50 matching lines @@
 
   Node parseNode(DiagnosticListener listener) => node;
 
   // A [ClosureClassElement] is nested inside a function or initializer in terms
   // of [enclosingElement], but still has to be treated as a top-level
   // element.
   bool get isTopLevel => true;
 
   get enclosingElement => methodElement;
 
-  accept(ElementVisitor visitor) => visitor.visitClosureClassElement(this);
+  accept(ElementVisitor visitor, arg) {
+    return visitor.visitClosureClassElement(this, arg);
+  }
 }
 
 /// A local variable that contains the box object holding the [BoxFieldElement]
 /// fields.
 class BoxLocal extends Local {
   final String name;
   final ExecutableElement executableContext;
 
   BoxLocal(this.name, this.executableContext);
 }
 
 // TODO(ngeoffray, ahe): These classes continuously cause problems.  We need to
 // find a more general solution.
 class BoxFieldElement extends ElementX
     implements TypedElement, CapturedVariable, FieldElement {
   final BoxLocal box;
 
   BoxFieldElement(String name, this.variableElement, BoxLocal box)
       : this.box = box,
         super(name, ElementKind.FIELD, box.executableContext);
 
   DartType computeType(Compiler compiler) => type;
 
   DartType get type => variableElement.type;
 
   final VariableElement variableElement;
 
-  accept(ElementVisitor visitor) => visitor.visitBoxFieldElement(this);
+  accept(ElementVisitor visitor, arg) {
+    return visitor.visitBoxFieldElement(this, arg);
+  }
 
   @override
   bool get hasNode => false;
 
   @override
   bool get hasResolvedAst => false;
 
   @override
   Expression get initializer {
     throw new UnsupportedError("BoxFieldElement.initializer");
@@ skipping 831 matching lines @@
 
   String get name => typeVariable.name;
 
   int get hashCode => typeVariable.hashCode;
 
   bool operator ==(other) {
     if (other is! TypeVariableLocal) return false;
     return typeVariable == other.typeVariable;
   }
 }