Ensure that unmangled private names are unique.

sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.dart

 // Copyright (c) 2013, 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 ClassEmitter extends CodeEmitterHelper {
   /**
    * Documentation wanted -- johnniwinther
    *
@@ skipping 136 matching lines @@
         // constructors, so we don't need the fields unless we are generating
         // accessors at runtime.
         if (!classIsNative || needsAccessor) {
           var metadata = task.metadataEmitter.buildMetadataFunction(field);
           if (metadata != null) {
             hasMetadata = true;
           } else {
             metadata = new jsAst.LiteralNull();
           }
           fieldMetadata.add(metadata);
-          recordMangledField(field, accessorName, field.name);
+          recordMangledField(field, accessorName,
+              namer.privateName(field.library, field.name));
           String fieldName = name;
           String fieldCode = '';
           String reflectionMarker = '';
           if (!needsAccessor) {
             // Emit field for constructor generation.
             assert(!classIsNative);
           } else {
             // Emit (possibly renaming) field name so we can add accessors at
             // runtime.
             if (name != accessorName) {
@@ skipping 447 matching lines @@
       computeTypeVariable =
           js(r'this.$builtinTypeInfo && this.$builtinTypeInfo[#]', index);
     }
     jsAst.Expression convertRtiToRuntimeType =
         namer.elementAccess(backend.findHelper('convertRtiToRuntimeType'));
     builder.addProperty(name,
         js('function () { return #(#) }',
             [convertRtiToRuntimeType, computeTypeVariable]));
   }
 }