Use closure conversion in new dart2js backend.

pkg/compiler/lib/src/tree_ir/tree_ir_tracer.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 tree_ir_tracer;
 
 import 'dart:async' show EventSink;
 import '../tracer.dart';
 import 'tree_ir_nodes.dart';
 import 'optimization/optimization.dart';
@@ skipping 133 matching lines @@
   visitExpressionStatement(ExpressionStatement node) {
     _addStatement(node);
     visitStatement(node.next);
   }
 
   visitFunctionDeclaration(FunctionDeclaration node) {
     _addStatement(node);
     visitStatement(node.next);
   }
 
+  visitSetField(SetField node) {
+    _addStatement(node);
+    visitStatement(node.next);
+  }
+
 }
 
 class TreeTracer extends TracerUtil with StatementVisitor, PassMixin {
   final EventSink<String> output;
 
   TreeTracer(this.output);
 
   Names names;
   BlockCollector collector;
   int statementCounter;
@@ skipping 106 matching lines @@
   }
 
   visitExpressionStatement(ExpressionStatement node) {
     printStatement(null, expr(node.expression));
   }
 
   visitFunctionDeclaration(FunctionDeclaration node) {
     printStatement(null, 'function ${node.definition.element.name}');
   }
 
+  visitSetField(SetField node) {
+    String object = expr(node.object);
+    String field = node.field.name;
+    String value = expr(node.value);
+    if (SubexpressionVisitor.usesInfixNotation(node.object)) {
+      object = '($object)';
+    }
+    printStatement(null, '$object.$field = $value');
+  }
+
   String expr(Expression e) {
     return e.accept(new SubexpressionVisitor(names));
   }
 }
 
 class SubexpressionVisitor extends ExpressionVisitor<String> {
   Names names;
 
   SubexpressionVisitor(this.names);
 
@@ skipping 71 matching lines @@
   }
 
   String visitThis(This node) {
     return "this";
   }
 
   String visitReifyTypeVar(ReifyTypeVar node) {
     return "typevar [${node.typeVariable.name}]";
   }
 
-  bool usesInfixNotation(Expression node) {
+  static bool usesInfixNotation(Expression node) {
     return node is Conditional || node is LogicalOperator;
   }
 
   String visitConditional(Conditional node) {
     String condition = visitExpression(node.condition);
     String thenExpr = visitExpression(node.thenExpression);
     String elseExpr = visitExpression(node.elseExpression);
     return "$condition ? $thenExpr : $elseExpr";
   }
 
@@ skipping 28 matching lines @@
   }
 
   String visitFieldInitializer(FieldInitializer node) {
     throw "$node should not be visited by $this";
   }
 
   String visitSuperInitializer(SuperInitializer node) {
     throw "$node should not be visited by $this";
   }
 
+  String visitGetField(GetField node) {
+    String object = visitExpression(node.object);
+    String field = node.field.name;
+    if (usesInfixNotation(node.object)) {
+      object = '($object)';
+    }
+    return '$object.$field';
+  }
+
+  String visitCreateBox(CreateBox node) {
+    return 'CreateBox';
+  }
+
+  String visitCreateClosureClass(CreateClosureClass node) {
+    String className = node.classElement.name;
+    String arguments = node.arguments.map(visitExpression).join(', ');
+    return 'CreateClosure $className($arguments)';
+  }
+
 }
 
 /**
  * Invents (and remembers) names for Variables that do not have an associated
  * identifier.
  *
  * In case a variable is named v0, v1, etc, it may be assigned a different
  * name to avoid clashing with a previously synthesized variable name.
  */
 class Names {
   final Map<Variable, String> _names = {};
   final Set<String> _usedNames = new Set();
   int _counter = 0;
 
   String varName(Variable v) {
     String name = _names[v];
     if (name == null) {
       String prefix = v.element == null ? 'v' : '${v.element.name}_';
       while (name == null || _usedNames.contains(name)) {
         name = "$prefix${_counter++}";
       }
       _names[v] = name;
       _usedNames.add(name);
     }
     return name;
   }
 }