Access BackendUsage through ClosedWorld

pkg/compiler/lib/src/inferrer/node_tracer.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 compiler.src.inferrer.node_tracer;
 
 import '../common/names.dart' show Identifiers;
 import '../compiler.dart' show Compiler;
 import '../elements/elements.dart';
 import '../types/types.dart' show ContainerTypeMask, MapTypeMask;
@@ skipping 432 matching lines @@
   }
 
   void visitMemberTypeInformation(MemberTypeInformation info) {
     if (info.isClosurized) {
       bailout('Returned from a closurized method');
     }
     if (isClosure(info.element)) {
       bailout('Returned from a closure');
     }
     if (info.element.isField &&
-        !inferrer.compiler.backend
-            .canFieldBeUsedForGlobalOptimizations(info.element)) {
+        !inferrer.compiler.backend.canFieldBeUsedForGlobalOptimizations(
+            info.element, inferrer.closedWorld)) {
       bailout('Escape to code that has special backend treatment');
     }
     addNewEscapeInformation(info);
   }
 
   void visitParameterTypeInformation(ParameterTypeInformation info) {
     ParameterElement element = info.element;
     if (inferrer.isNativeMember(element.functionDeclaration)) {
       bailout('Passed to a native method');
     }
     if (!inferrer.compiler.backend
         .canFunctionParametersBeUsedForGlobalOptimizations(
-            element.functionDeclaration)) {
+            element.functionDeclaration, inferrer.closedWorld)) {
       bailout('Escape to code that has special backend treatment');
     }
     if (isParameterOfListAddingMethod(element) ||
         isParameterOfMapAddingMethod(element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }