Rollback of r12868, r12849 in trunk branch.

src/objects-inl.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 116 matching lines @@
   void holder::set_##name(bool value) {                    \
     set_##field(BooleanBit::set(field(), offset, value));  \
   }
 
 
 bool Object::IsFixedArrayBase() {
   return IsFixedArray() || IsFixedDoubleArray();
 }
 
 
-// External objects are not extensible, so the map check is enough.
-bool Object::IsExternal() {
-  return Object::IsHeapObject() &&
-      HeapObject::cast(this)->map() ==
-      HeapObject::cast(this)->GetHeap()->external_map();
-}
-
-
 bool Object::IsInstanceOf(FunctionTemplateInfo* expected) {
   // There is a constraint on the object; check.
   if (!this->IsJSObject()) return false;
   // Fetch the constructor function of the object.
   Object* cons_obj = JSObject::cast(this)->map()->constructor();
   if (!cons_obj->IsJSFunction()) return false;
   JSFunction* fun = JSFunction::cast(cons_obj);
   // Iterate through the chain of inheriting function templates to
   // see if the required one occurs.
   for (Object* type = fun->shared()->function_data();
@@ skipping 5394 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_