Access NativeData only through ClosedWorld

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

 // Copyright (c) 2016, 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 js_backend.serialization;
 
 import '../common/backend_api.dart' show BackendSerialization;
 import '../elements/elements.dart';
 import '../elements/resolution_types.dart';
 import '../elements/types.dart';
@@ skipping 36 matching lines @@
 const Key NATIVE_METHOD_BEHAVIOR = const Key('nativeMethodBehavior');
 const Key NATIVE_FIELD_LOAD_BEHAVIOR = const Key('nativeFieldLoadBehavior');
 const Key NATIVE_FIELD_STORE_BEHAVIOR = const Key('nativeFieldStoreBehavior');
 
 class JavaScriptBackendSerializer implements SerializerPlugin {
   final JavaScriptBackend _backend;
 
   JavaScriptBackendSerializer(this._backend);
 
   NativeBasicDataImpl get nativeBasicData => _backend.nativeBasicData;
-  NativeDataImpl get nativeData => _backend.nativeData;
+  NativeDataBuilderImpl get nativeData => _backend.nativeDataBuilder;
 
   @override
   void onElement(Element element, ObjectEncoder createEncoder(String tag)) {
     ObjectEncoder encoder;
     ObjectEncoder getEncoder() {
       return encoder ??= createEncoder(_BACKEND_DATA_TAG);
     }
 
     String jsInteropLibraryName = nativeData.jsInteropLibraryNames[element];
     if (jsInteropLibraryName != null) {
@@ skipping 44 matching lines @@
   }
 }
 
 class JavaScriptBackendDeserializer implements DeserializerPlugin {
   final JavaScriptBackend _backend;
 
   JavaScriptBackendDeserializer(this._backend);
 
   NativeBasicDataBuilderImpl get nativeBasicData =>
       _backend.nativeBasicDataBuilder;
-  NativeDataImpl get nativeData => _backend.nativeData;
+  NativeDataBuilderImpl get nativeData => _backend.nativeDataBuilder;
 
   @override
   void onElement(Element element, ObjectDecoder getDecoder(String tag)) {
     ObjectDecoder decoder = getDecoder(_BACKEND_DATA_TAG);
     if (decoder != null) {
       if (element is LibraryElement) {
         String jsInteropLibraryName =
             decoder.getString(JS_INTEROP_LIBRARY_NAME, isOptional: true);
         if (jsInteropLibraryName != null) {
           nativeData.jsInteropLibraryNames[element] = jsInteropLibraryName;
@@ skipping 155 matching lines @@
       behavior.codeTemplate = js.js.parseForeignJS(behavior.codeTemplateText);
     }
 
     behavior.throwBehavior =
         decoder.getEnum(THROW_BEHAVIOR, NativeThrowBehavior.values);
     behavior.isAllocation = decoder.getBool(IS_ALLOCATION);
     behavior.useGvn = decoder.getBool(USE_GVN);
     return behavior;
   }
 }