Let DescriptorArray::Append insert at proper position, avoiding need for resorting.

src/factory.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 478 matching lines @@
  private:
   Isolate* isolate() { return reinterpret_cast<Isolate*>(this); }
 
   Handle<JSFunction> NewFunctionHelper(Handle<String> name,
                                        Handle<Object> prototype);
 
   Handle<JSFunction> NewFunctionWithoutPrototypeHelper(
       Handle<String> name,
       LanguageMode language_mode);
 
-  Handle<DescriptorArray> CopyAppendCallbackDescriptors(
-      Handle<DescriptorArray> array,
-      Handle<Object> descriptors);
+  void CopyAppendCallbackDescriptors(Handle<Map> map,
+                                     Handle<Object> descriptors);
 
   // Create a new map cache.
   Handle<MapCache> NewMapCache(int at_least_space_for);
 
   // Update the map cache in the global context with (keys, map)
   Handle<MapCache> AddToMapCache(Handle<Context> context,
                                  Handle<FixedArray> keys,
                                  Handle<Map> map);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FACTORY_H_