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 2315 matching lines @@
   // Casting.
   static inline JSObject* cast(Object* obj);
 
   // Disalow further properties to be added to the object.
   static Handle<Object> PreventExtensions(Handle<JSObject> object);
   MUST_USE_RESULT MaybeObject* PreventExtensions();
 
   // ES5 Object.freeze
   MUST_USE_RESULT MaybeObject* Freeze(Isolate* isolate);
 
+
+  // Called the first time an object is observed with ES7 Object.observe.
+  MUST_USE_RESULT MaybeObject* SetObserved(Isolate* isolate);
+
   // Copy object
   MUST_USE_RESULT MaybeObject* DeepCopy(Isolate* isolate);
 
   // Dispatched behavior.
   void JSObjectShortPrint(StringStream* accumulator);
   DECLARE_PRINTER(JSObject)
   DECLARE_VERIFIER(JSObject)
 #ifdef OBJECT_PRINT
   inline void PrintProperties() {
     PrintProperties(stdout);
@@ skipping 3124 matching lines @@
   MUST_USE_RESULT MaybeObject* CopyAddDescriptor(Descriptor* descriptor,
                                                  TransitionFlag flag);
   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);
@@ skipping 4314 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_