dart2js cps: More aggressive operator specialization.

pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart

 // Copyright (c) 2015, 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.optimization.pull_into_initializers;
 
 import 'optimization.dart' show Pass;
 import '../tree_ir_nodes.dart';
 
 /// Where a variable has been assigned.
@@ skipping 150 matching lines @@
   }
 
   Statement visitFor(For node) {
     return node;
   }
 
   Statement visitTry(Try node) {
     return node;
   }
 
-  Statement visitNullCheck(NullCheck node) {
+  Statement visitReceiverCheck(ReceiverCheck node) {
     if (node.condition != null) {
       node.condition = visitExpression(node.condition);
       // The value occurs in conditional context, so don't pull from that.
     } else {
       node.value = visitExpression(node.value);
     }
     return node;
   }
 
   Expression visitAssign(Assign node) {
@@ skipping 182 matching lines @@
 
   @override
   Expression visitForeignExpression(ForeignExpression node) {
     rewriteList(node.arguments);
     if (node.nativeBehavior.sideEffects.hasSideEffects()) {
       ++impureCounter;
     }
     return node;
   }
 }