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 917 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);
     // 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;
       Node parameterNode = variableDefinitions.definitions.nodes.head;
+      if (variableDefinitions.type !== null) {
+        resolveTypeAnnotation(variableDefinitions.type);
+      }
       initializerDo(parameterNode, (n) => n.accept(this));
       // Field parameters (this.x) are not visible inside the constructor. The
       // fields they reference are visible, but must be resolved independently.
       if (element.kind == ElementKind.FIELD_PARAMETER) {
         useElement(parameterNode, element);
       } else {
         defineElement(variableDefinitions.definitions.nodes.head, element);
       }
       parameterNodes = parameterNodes.tail;
     });
@@ skipping 1246 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";
   }
 }