Introduce OpenWorld.

pkg/compiler/lib/src/universe/use.dart

 // Copyright (c) 2012, 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.
 
 /// This library defines individual world impacts.
 ///
 /// We call these building blocks `uses`. Each `use` is a single impact of the
 /// world. Some example uses are:
 ///
 ///  * an invocation of a top level function
@@ skipping 20 matching lines @@
 /// The use of a dynamic property. [selector] defined the name and kind of the
 /// property and [mask] defines the known constraint for the object on which
 /// the property is accessed.
 class DynamicUse {
   final Selector selector;
   final ReceiverConstraint mask;
 
   DynamicUse(this.selector, this.mask);
 
   bool appliesUnnamed(Element element, ClassWorld world) {
-    return selector.appliesUnnamed(element, world) &&
+    return selector.appliesUnnamed(element, world.backend) &&
         (mask == null || mask.canHit(element, selector, world));
   }
 
   DynamicUseKind get kind {
     if (selector.isGetter) {
       return DynamicUseKind.GET;
     } else if (selector.isSetter) {
       return DynamicUseKind.SET;
     } else {
       return DynamicUseKind.INVOKE;
@@ skipping 258 matching lines @@
   }
 
   bool operator ==(other) {
     if (identical(this, other)) return true;
     if (other is! TypeUse) return false;
     return type == other.type && kind == other.kind;
   }
 
   String toString() => 'TypeUse($type,$kind)';
 }