Add map transition for observed objects

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 5465 matching lines @@
   MUST_USE_RESULT MaybeObject* CopyInsertDescriptor(Descriptor* descriptor,
                                                     TransitionFlag flag);
   MUST_USE_RESULT MaybeObject* CopyReplaceDescriptor(
       DescriptorArray* descriptors,
       Descriptor* descriptor,
       int index,
       TransitionFlag flag);
   MUST_USE_RESULT MaybeObject* AsElementsKind(ElementsKind kind);
   MUST_USE_RESULT MaybeObject* CopyAsElementsKind(ElementsKind kind,
                                                   TransitionFlag flag);
-
+  MUST_USE_RESULT MaybeObject* CopyForObserved();
   MUST_USE_RESULT MaybeObject* CopyNormalized(PropertyNormalizationMode mode,
                                               NormalizedMapSharingMode sharing);
 
   inline void AppendDescriptor(Descriptor* desc,
                                const DescriptorArray::WhitenessWitness&);
 
   // Returns a copy of the map, with all transitions dropped from the
   // instance descriptors.
   static Handle<Map> Copy(Handle<Map> map);
   MUST_USE_RESULT MaybeObject* Copy();
@@ skipping 4313 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_