Split NativeData

pkg/compiler/lib/src/js_backend/backend_usage.dart

Index: pkg/compiler/lib/src/js_backend/backend_usage.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend_usage.dart b/pkg/compiler/lib/src/js_backend/backend_usage.dart
index 6634c4e3356fe6deca613b4d273e05c557d2a311..629273a24146a0e276891d82c4aa80f05476c670 100644
--- a/pkg/compiler/lib/src/js_backend/backend_usage.dart
+++ b/pkg/compiler/lib/src/js_backend/backend_usage.dart
@@ -3,15 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import '../common.dart';
-import '../common/resolution.dart' show Resolution;
 import '../common_elements.dart';
 import '../elements/elements.dart';
-import '../elements/entities.dart';
 import '../elements/resolution_types.dart';
-import '../universe/selector.dart';
-import '../universe/use.dart';
-import '../universe/world_impact.dart'
-    show WorldImpact, WorldImpactBuilder, WorldImpactBuilderImpl;
 import '../util/util.dart' show Setlet;
 import 'backend_helpers.dart';
 import 'backend_impact.dart';