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 1ed955de6b8697b24c611d8392df2f5cdc6dd14d..433fdaee6a5eef9f2a8b6887a197fbd24ff36312 100644
--- a/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
+++ b/pkg/compiler/lib/src/js_emitter/code_emitter_task.dart
@@ -51,11 +51,11 @@ 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);
   }
 
   /// Returns the closure expression of a static function.