Always require exact maps.

src/objects.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 130 matching lines @@
 //         - CodeCache
 //
 // Formats of Object*:
 //  Smi:        [31 bit signed int] 0
 //  HeapObject: [32 bit direct pointer] (4 byte aligned) | 01
 //  Failure:    [30 bit signed int] 11
 
 namespace v8 {
 namespace internal {
 
-enum CompareMapMode {
-  REQUIRE_EXACT_MAP,
-  ALLOW_ELEMENT_TRANSITION_MAPS
-};
-
 enum KeyedAccessStoreMode {
   STANDARD_STORE,
   STORE_TRANSITION_SMI_TO_OBJECT,
   STORE_TRANSITION_SMI_TO_DOUBLE,
   STORE_TRANSITION_DOUBLE_TO_OBJECT,
   STORE_TRANSITION_HOLEY_SMI_TO_OBJECT,
   STORE_TRANSITION_HOLEY_SMI_TO_DOUBLE,
   STORE_TRANSITION_HOLEY_DOUBLE_TO_OBJECT,
   STORE_AND_GROW_NO_TRANSITION,
   STORE_AND_GROW_TRANSITION_SMI_TO_OBJECT,
@@ skipping 9152 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_