Add NativeEnqueuer to work with the Enqueuer.

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index bcc77f7f841a2e83f0dc097690dd63299a88da98..a24e9376d795e984d89c4b9d7a6ab438df791888 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -816,9 +816,13 @@ class JavaScriptBackend extends Backend {
     invalidateAfterCodegen.clear();
   }
 
-  void processNativeClasses(Enqueuer world,
-                            Collection<LibraryElement> libraries) {
-    native.processNativeClasses(world, emitter, libraries);
+
+  native.NativeEnqueuer nativeResolutionEnqueuer(Enqueuer world) {
+    return new native.NativeResolutionEnqueuer(world, compiler);
+  }
+
+  native.NativeEnqueuer nativeCodegenEnqueuer(Enqueuer world) {
+    return new native.NativeCodegenEnqueuer(world, compiler, emitter);
   }
 
   void assembleProgram() {