Set up a stub pipline for using the new cps-based ir to generate js.

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.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_nodes;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart' as values;
 import '../cps_ir/cps_ir_nodes.dart' as cps_ir;
 import '../dart_types.dart' show DartType, GenericType;
 import '../elements/elements.dart';
 import '../universe/universe.dart';
 import '../universe/universe.dart' show Selector;
 
-
 // The Tree language is the target of translation out of the CPS-based IR.
 //
 // The translation from CPS to Dart consists of several stages.  Among the
 // stages are translation to direct style, translation out of SSA, eliminating
 // unnecessary names, recognizing high-level control constructs.  Combining
 // these separate concerns is complicated and the constraints of the CPS-based
 // language do not permit a multi-stage translation.
 //
 // For that reason, CPS is translated to the direct-style language Tree.
 // Translation out of SSA, unnaming, and control-flow, as well as 'instruction
@@ skipping 629 matching lines @@
   visitFunctionDeclaration(FunctionDeclaration node) {
     visitFunctionDefinition(node.definition);
     visitStatement(node.next);
   }
 
   visitExpressionStatement(ExpressionStatement node) {
     visitExpression(node.expression);
     visitStatement(node.next);
   }
 }