dart2js cps: Reanalyze subterms when they get inserted.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart

 // Copyright (c) 2013, 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;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart' as values show ConstantValue;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
@@ skipping 205 matching lines @@
   LetMutable(this.variable, Primitive value)
       : this.value = new Reference<Primitive>(value);
 
   Expression plug(Expression expr) {
     return body = expr;
   }
 
   accept(Visitor visitor) => visitor.visitLetMutable(this);
 }
 
-abstract class Invoke {
+abstract class Invoke implements Expression {
   Selector get selector;
   List<Reference<Primitive>> get arguments;
+  Reference<Continuation> get continuation;
 }
 
 /// Represents a node with a child node, which can be accessed through the
 /// `body` member. A typical usage is when removing a node from the CPS graph:
 ///
 ///     Node child          = node.body;
 ///     InteriorNode parent = node.parent;
 ///
 ///     child.parent = parent;
 ///     parent.body  = child;
@@ skipping 1030 matching lines @@
   const RemovalVisitor();
 
   processReference(Reference reference) {
     reference.unlink();
   }
 
   static void remove(Node node) {
     (const RemovalVisitor()).visit(node);
   }
 }