Use closure conversion in new dart2js backend.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.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 dart2js.ir_nodes_sexpr;
 
 import '../constants/values.dart';
 import '../util/util.dart';
 import 'cps_ir_nodes.dart';
 
@@ skipping 210 matching lines @@
     return '$indentation(DeclareFunction $name =\n'
            '$function in\n'
            '$body)';
   }
 
   String visitIsTrue(IsTrue node) {
     String value = access(node.value);
     return '(IsTrue $value)';
   }
 
+  String visitSetField(SetField node) {
+    String object = access(node.object);
+    String field = node.field.name;
+    String value = access(node.value);
+    String body = indentBlock(() => visit(node.body));
+    return '$indentation(SetField $object.$field = $value in\n$body)';

[Kevin Millikin (Google), 2015/01/13 08:25:36]

I don't really want '.', '=', or 'in' here.  This representation is abstract
syntax, and they just make parsing harder.

Though the expression has a body, it's not really a scope (setting a field is
assignment, not binding).  I'd prefer it formatted like setq in Lisp or set! in
Scheme:

String body = visit(node.body);
return '$indentation(SetField $object $field $value)\n$body';

[asgerf, 2015/01/13 10:04:26]

Yeah, I must have been half-thinking about the IR tracer when I wrote this.

+  }
+
+  String visitGetField(GetField node) {
+    String object = access(node.object);
+    String field = node.field.toString();
+    return '(GetField $object.$field)';

[Kevin Millikin (Google), 2015/01/13 08:25:36]

No dot:

'(GetField $object $field)'

+  }
+
+  String visitCreateBox(CreateBox node) {
+    return '(CreateBox)';
+  }
+
+  String visitCreateClosureClass(CreateClosureClass node) {
+    String className = node.classElement.name;
+    String arguments = node.arguments.map(access).join(' ');
+    return '(CreateClosureClass $className $arguments)';

[Kevin Millikin (Google), 2015/01/13 08:25:36]

'(CreateClosureClass $className ($arguments))'

+  }
+
   String visitIdentical(Identical node) {
     String left = access(node.left);
     String right = access(node.right);
     return '(Identical $left $right)';
   }
 
   String visitInterceptor(Interceptor node) {
     return '(Interceptor ${node.input})';
   }
 }
@@ skipping 90 matching lines @@
   void setReturnContinuation(Continuation node) {
     assert(!_names.containsKey(node) || _names[node] == 'return');
     _names[node] = 'return';
   }
 
   String getName(Node node) {
     assert(_names.containsKey(node));
     return _names[node];
   }
 }