Fix dart2dart and dart2js build.

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 2320 matching lines @@
                                     Node diagnosticNode,
                                     SourceString constructorName) {
     cls.ensureResolved(compiler);
     Element result = cls.lookupConstructor(cls.name, constructorName);
     if (result === null) {
       String fullConstructorName = cls.name.slowToString();
       if (constructorName !== const SourceString('')) {
         fullConstructorName = '$fullConstructorName'
                               '.${constructorName.slowToString()}';
       }
-      ResolutionWarning message  =
+      ResolutionWarning warning  =
           new ResolutionWarning(MessageKind.CANNOT_FIND_CONSTRUCTOR,
                                 [fullConstructorName]);
-      compiler.reportWarning(diagnosticNode, message);
-      return new ErroneousFunctionElement(message, cls);
+      compiler.reportWarning(diagnosticNode, warning);
+      return new ErroneousFunctionElement(warning.message, cls);
     }
     return result;
   }
 
   visitNewExpression(NewExpression node) {
     Node selector = node.send.selector;
     Element e = visit(selector);
     if (!Element.isInvalid(e) && e.kind === ElementKind.CLASS) {
       ClassElement cls = e;
       cls.ensureResolved(compiler);
@@ skipping 170 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";
   }
   String toString() => '$element';
 }