dart2js: First part of native support in the new emitter.

pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart

Index: pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
index 3fa2c8f1683675b33c93a84dfdf1b49a4b13622c..80b6b9881fbca092b21b732656ef71260c632e24 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
@@ -944,14 +944,15 @@ class OldEmitter implements Emitter {
       mainCallClosure = backend.emitter.staticFunctionAccess(main);
     }
 
-    bool initializeAffinityTag = backend.needToInitializeIsolateAffinityTag;
-    jsAst.Statement nativeBoilerPlate =
-        NativeGenerator.generateIsolateAffinityTagInitialization(
-        generateEmbeddedGlobalAccess,
-        initializeIsolateAffinityTag: initializeAffinityTag,
-        initializeDispatchProperty: backend.needToInitializeDispatchProperty);
-    buffer.write(jsAst.prettyPrint(nativeBoilerPlate,
-                                   compiler, monitor: compiler.dumpInfoTask));
+    if (NativeGenerator.needsIsolateAffinityTagInitialization(backend)) {
+      jsAst.Statement nativeBoilerPlate =
+          NativeGenerator.generateIsolateAffinityTagInitialization(
+              backend,
+              generateEmbeddedGlobalAccess,
+              js("convertToFastObject", []));
+      buffer.write(jsAst.prettyPrint(nativeBoilerPlate,
+                                     compiler, monitor: compiler.dumpInfoTask));
+    }
 
     jsAst.Expression currentScriptAccess =
         generateEmbeddedGlobalAccess(embeddedNames.CURRENT_SCRIPT);