Access BackendUsage through ClosedWorld

pkg/compiler/lib/src/kernel/kernel_strategy.dart

 // Copyright (c) 2017, 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.kernel.frontend_strategy;
 
 import '../closure.dart';
 import '../backend_strategy.dart';
 import '../common.dart';
 import '../common_elements.dart';
@@ skipping 95 matching lines @@
 
   RuntimeTypesNeedBuilder createRuntimeTypesNeedBuilder() {
     return new RuntimeTypesNeedBuilderImpl(
         elementEnvironment, elementMap.types);
   }
 
   ResolutionWorldBuilder createResolutionWorldBuilder(
       NativeBasicData nativeBasicData,
       NativeDataBuilder nativeDataBuilder,
       InterceptorDataBuilder interceptorDataBuilder,
+      BackendUsageBuilder backendUsageBuilder,
       SelectorConstraintsStrategy selectorConstraintsStrategy) {
-    return new KernelResolutionWorldBuilder(elementMap, nativeBasicData,
-        nativeDataBuilder, interceptorDataBuilder, selectorConstraintsStrategy);
+    return new KernelResolutionWorldBuilder(
+        elementMap,
+        nativeBasicData,
+        nativeDataBuilder,
+        interceptorDataBuilder,
+        backendUsageBuilder,
+        selectorConstraintsStrategy);
   }
 
   WorkItemBuilder createResolutionWorkItemBuilder(
       NativeBasicData nativeBasicData,
       NativeDataBuilder nativeDataBuilder,
       ImpactTransformer impactTransformer) {
     return new KernelWorkItemBuilder(
         elementMap, nativeBasicData, nativeDataBuilder, impactTransformer);
   }
 }
@@ skipping 108 matching lines @@
   Sorter get sorter =>
       throw new UnimplementedError('KernelBackendStrategy.sorter');
 
   @override
   void convertClosures(ClosedWorldRefiner closedWorldRefiner) {
     // TODO(johnniwinther,efortuna): Compute closure classes for kernel based
     // elements.
     throw new UnimplementedError('KernelBackendStrategy.createClosureClasses');
   }
 }