dart2dart: Introduce Renamer that is used by renaming unparser

lib/compiler/implementation/resolver.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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   Type getType(TypeAnnotation annotation);
 }
 
@@ skipping 923 matching lines @@
   Type useType(TypeAnnotation annotation, Type type) {
     if (type !== null) {
       mapping.setType(annotation, type);
       useElement(annotation, type.element);
     }
     return type;
   }
 
   void setupFunction(FunctionExpression node, FunctionElement function) {
     context = new MethodScope(context, function);
+    if (node.returnType !== null) resolveTypeAnnotation(node.returnType);

[ahe, 2012/08/02 18:37:14]

I think you should be able to revert this since you should be using the
FunctionElement moving forward.

     // Put the parameters in scope.
     FunctionSignature functionParameters =
         function.computeSignature(compiler);
     Link<Node> parameterNodes = node.parameters.nodes;
     functionParameters.forEachParameter((Element element) {
       if (element == functionParameters.optionalParameters.head) {
         NodeList nodes = parameterNodes.head;
         parameterNodes = nodes.nodes;
       }
       VariableDefinitions variableDefinitions = parameterNodes.head;
@@ skipping 1257 matching lines @@
 
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) {
     return library.find(name);
   }
 
   Element add(Element newElement) {
     throw "Cannot add an element in the top scope";
   }
 }