Make __proto__ a real JavaScript accessor property.

src/heap.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 132 matching lines @@
   V(Map, module_context_map, ModuleContextMap)                                 \
   V(Map, global_context_map, GlobalContextMap)                                 \
   V(Map, oddball_map, OddballMap)                                              \
   V(Map, message_object_map, JSMessageObjectMap)                               \
   V(Map, foreign_map, ForeignMap)                                              \
   V(HeapNumber, nan_value, NanValue)                                           \
   V(HeapNumber, infinity_value, InfinityValue)                                 \
   V(HeapNumber, minus_zero_value, MinusZeroValue)                              \
   V(Map, neander_map, NeanderMap)                                              \
   V(JSObject, message_listeners, MessageListeners)                             \
-  V(Foreign, prototype_accessors, PrototypeAccessors)                          \
   V(UnseededNumberDictionary, code_stubs, CodeStubs)                           \
   V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache)      \
   V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache)        \
   V(Code, js_entry_code, JsEntryCode)                                          \
   V(Code, js_construct_entry_code, JsConstructEntryCode)                       \
   V(FixedArray, natives_source_cache, NativesSourceCache)                      \
   V(Object, last_script_id, LastScriptId)                                      \
   V(Script, empty_script, EmptyScript)                                         \
   V(Smi, real_stack_limit, RealStackLimit)                                     \
   V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames)        \
@@ skipping 2865 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_