Overhaul tree IR visitor and rename IR classes.

pkg/analyzer2dart/lib/src/cps_generator.dart

 // Copyright (c) 2014, 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 analyzer2dart.cps_generator;
 
 import 'package:analyzer/analyzer.dart';
 
 import 'package:compiler/src/dart_types.dart' as dart2js;
 import 'package:compiler/src/elements/elements.dart' as dart2js;
@@ skipping 37 matching lines @@
 
   @override
   ir.FieldDefinition visitTopLevelVariableElement(
       analyzer.TopLevelVariableElement element) {
     CpsGeneratingVisitor visitor = new CpsGeneratingVisitor(converter, element);
     VariableDeclaration variableDeclaration = node;
     return visitor.handleFieldDeclaration(element, variableDeclaration);
   }
 
   @override
-  ir.ExecutableDefinition visitConstructorElement(
-      analyzer.ConstructorElement element) {
+  ir.RootNode visitConstructorElement(analyzer.ConstructorElement element) {
     CpsGeneratingVisitor visitor = new CpsGeneratingVisitor(converter, element);
     if (!element.isFactory) {
       ConstructorDeclaration constructorDeclaration = node;
       FunctionBody body;
       if (constructorDeclaration != null) {
         body = constructorDeclaration.body;
       } else {
         assert(element.isSynthetic);
       }
       return visitor.handleConstructorDeclaration(element, body);
@@ skipping 513 matching lines @@
     irBuilder.buildTry(
         tryStatementInfo: new TryStatementInfo(),
         buildTryBlock: subbuild(node.body),
         catchClauseInfos: catchClauseInfos);
   }
 }
 
 class NullCapturedVariables extends DartCapturedVariables {
   NullCapturedVariables() : super(null);
 }