Dart2js option to dump info about compilation

tests/compiler/dart2js/mock_compiler.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 mock_compiler;
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'dart:collection';
 
 import '../../../sdk/lib/_internal/compiler/compiler.dart' as api;
 import '../../../sdk/lib/_internal/compiler/implementation/elements/elements.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/resolution/resolution.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/util/util.dart';
 import 'parser_helper.dart';
 
 import '../../../sdk/lib/_internal/compiler/implementation/elements/modelx.dart'
     show ElementX,
          LibraryElementX,
-         ErroneousElementX;
+         ErroneousElementX,
+         FunctionElementX;
 
 import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart'
     hide TreeElementMapping;
 
 import '../../../sdk/lib/_internal/compiler/implementation/deferred_load.dart'
     show DeferredLoadTask;
 
 
 class WarningMessage {
   Spannable node;
@@ skipping 354 matching lines @@
     if (visitor.scope is LibraryScope) {
       visitor.scope = new MethodScope(visitor.scope, element);
     }
     visitor.visit(tree);
     visitor.scope = new LibraryScope(element.getLibrary());
     return visitor.mapping;
   }
 
   resolverVisitor() {
     Element mockElement =
-        new ElementX('', ElementKind.FUNCTION, mainApp.entryCompilationUnit);
+      new FunctionElementX('', ElementKind.FUNCTION, Modifiers.EMPTY,
+                           mainApp.entryCompilationUnit, false);
     ResolverVisitor visitor =
         new ResolverVisitor(this, mockElement,
                             new CollectingTreeElements(mockElement));
     visitor.scope = new MethodScope(visitor.scope, mockElement);
     return visitor;
   }
 
   parseScript(String text, [LibraryElement library]) {
     if (library == null) library = mainApp;
     parseUnit(text, this, library, registerSource);
@@ skipping 101 matching lines @@
     } else {
       sourceFile = compiler.sourceFiles[uri.toString()];
     }
     if (sourceFile != null && begin != null && end != null) {
       print(sourceFile.getLocationMessage(message, begin, end, true, (x) => x));
     } else {
       print(message);
     }
   };
 }