dart2js: make "boilerplate" function in Native generator.

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

 // Copyright (c) 2014, 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.
 
 part of dart2js.js_emitter;
 
 
 class OldEmitter implements Emitter {
   final Compiler compiler;
   final CodeEmitterTask task;
@@ skipping 925 matching lines @@
         backend.isolateHelperLibrary.find(JavaScriptBackend.START_ROOT_ISOLATE);
       mainCallClosure = buildIsolateSetupClosure(main, isolateMain);
     } else if (compiler.hasIncrementalSupport) {
       mainCallClosure = js(
           'function() { return #(); }',
           backend.emitter.staticFunctionAccess(main));
     } else {
       mainCallClosure = backend.emitter.staticFunctionAccess(main);
     }
 
-    NativeGenerator nativeGenerator =
-        new NativeGenerator(generateEmbeddedGlobalAccess);
-    if (backend.needToInitializeIsolateAffinityTag) {
-      buffer.write(
-          jsAst.prettyPrint(
-              nativeGenerator.generateIsolateAffinityTagInitialization(),
-              compiler, monitor: compiler.dumpInfoTask));
-      buffer.write(N);
-    }
-    if (backend.needToInitializeDispatchProperty) {
-      assert(backend.needToInitializeIsolateAffinityTag);
-      buffer.write(
-          jsAst.prettyPrint(
-              nativeGenerator.generateDispatchPropertyNameInitialization(),
-              compiler, monitor: compiler.dumpInfoTask));
-      buffer.write(N);
-    }
+    bool initializeAffinityTag = backend.needToInitializeIsolateAffinityTag;
+    jsAst.Statement nativeBoilerPlate = NativeGenerator.generateBoilerPlate(
+        generateEmbeddedGlobalAccess,
+        initializeIsolateAffinityTag: initializeAffinityTag,
+        initializeDispatchProperty: backend.needToInitializeDispatchProperty);
+    buffer.write(jsAst.prettyPrint(nativeBoilerPlate,
+                                   compiler, monitor: compiler.dumpInfoTask));
 
     jsAst.Expression currentScriptAccess =
         generateEmbeddedGlobalAccess(embeddedNames.CURRENT_SCRIPT);
 
     addComment('BEGIN invoke [main].', buffer);
     // This code finds the currently executing script by listening to the
     // onload event of all script tags and getting the first script which
     // finishes. Since onload is called immediately after execution this should
     // not substantially change execution order.
     jsAst.Statement invokeMain = js.statement('''
@@ skipping 1066 matching lines @@
     for (Element element in compiler.enqueuer.codegen.newlyEnqueuedElements) {
       if (element.isInstanceMember) {
         cachedClassBuilders.remove(element.enclosingClass);
 
         nativeEmitter.cachedBuilders.remove(element.enclosingClass);
 
       }
     }
   }
 }