dart2js: support native classes in the new emitter.

pkg/compiler/lib/src/js_emitter/code_emitter_task.dart

Index: pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
diff --git a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
index 9307daf7cc22e8f4aac139eab6f5c02f339d6ac3..e384d9307257d937a99804feb10fc8464a7e6194 100644
--- a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
+++ b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
@@ -52,11 +52,11 @@ class CodeEmitterTask extends CompilerTask {
       : super(compiler),
         this.namer = namer,
         this.typeTestRegistry = new TypeTestRegistry(compiler) {
+    nativeEmitter = new NativeEmitter(this);
     oldEmitter = new OldEmitter(compiler, namer, generateSourceMap, this);
     emitter = USE_NEW_EMITTER
-        ? new new_js_emitter.Emitter(compiler, namer)
+        ? new new_js_emitter.Emitter(compiler, namer, nativeEmitter)
         : oldEmitter;
-    nativeEmitter = new NativeEmitter(this);
     metadataCollector = new MetadataCollector(compiler, emitter);
   }