dart2js: Add support for do/while loops to the CPS 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';
 
 /// A [Decorator] is a function used by [SExpressionStringifier] to augment the
-/// output produced for a node.  It can be provided to the constructor.
-typedef String Decorator(Node node, String s);
+/// output produced for a node or reference.  It can be provided to the
+/// constructor.
+typedef String Decorator(node, String s);
 
 /// Generate a Lisp-like S-expression representation of an IR node as a string.
 class SExpressionStringifier extends Indentation implements Visitor<String> {
   final _Namer namer = new _Namer();
 
   String newValueName(Primitive node) => namer.nameValue(node);
   String newContinuationName(Continuation node) => namer.nameContinuation(node);
   Decorator decorator;
 
   SExpressionStringifier([this.decorator]) {
     if (this.decorator == null) {
-      this.decorator = (Node node, String s) => s;
+      this.decorator = (node, String s) => s;
     }
   }
 
   String access(Reference<Definition> r) {
-    return decorator(r.definition, namer.getName(r.definition));
+    return decorator(r, namer.getName(r.definition));
   }
 
   String visitParameter(Parameter node) {
     return namer.nameParameter(node);
   }
 
   String visitMutableVariable(MutableVariable node) {
     return namer.nameMutableVariable(node);
   }
 
@@ skipping 398 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];
   }
 }