Add 'part of' in dart2js code.

lib/compiler/implementation/js_backend/emitter_no_eval.dart

 // Copyright (c) 2012, 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 js_backend;
+
 class CodeEmitterNoEvalTask extends CodeEmitterTask {
   CodeEmitterNoEvalTask(Compiler compiler,
                         Namer namer,
                         bool generateSourceMap)
       : super(compiler, namer, generateSourceMap);
 
   String get generateGetterSetterFunction {
     return """
 function() {
   throw 'Internal Error: no dynamic generation of getters and setters allowed';
@@ skipping 118 matching lines @@
         generateSetter(member, name, buffer);
       }
       if (needsCheckedSetter) {
         assert(!needsSetter);
         emitComma();
         generateCheckedSetter(member, name, buffer);
       }
     });
   }
 }