Prototype objects never share their map, and hence cannot be in deprecated state.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 6050 matching lines @@
   inline void set_migration_target(bool value);
   inline bool is_migration_target();
   inline void set_counter(int value);
   inline int counter();
   inline void deprecate();
   inline bool is_deprecated();
   inline bool CanBeDeprecated();
   // Returns a non-deprecated version of the input. If the input was not
   // deprecated, it is directly returned. Otherwise, the non-deprecated version
   // is found by re-transitioning from the root of the transition tree using the
   // descriptor array of the map. Returns NULL if no updated map is found.

[Igor Sheludko, 2015/02/23 17:55:02]

Returns empty handle...

-  // This method also applies any pending migrations along the prototype chain.
   static MaybeHandle<Map> TryUpdate(Handle<Map> map) WARN_UNUSED_RESULT;
-  // Same as above, but does not touch the prototype chain.
-  static MaybeHandle<Map> TryUpdateInternal(Handle<Map> map)
-      WARN_UNUSED_RESULT;
 
   // Returns a non-deprecated version of the input. This method may deprecate
   // existing maps along the way if encodings conflict. Not for use while
   // gathering type feedback. Use TryUpdate in those cases instead.
   static Handle<Map> Update(Handle<Map> map);
 
   static Handle<Map> CopyDropDescriptors(Handle<Map> map);
   static Handle<Map> CopyInsertDescriptor(Handle<Map> map,
                                           Descriptor* descriptor,
                                           TransitionFlag flag);
@@ skipping 4904 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_