Add map transition for observed objects

src/heap.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 169 matching lines @@
   V(Smi, real_stack_limit, RealStackLimit)                                     \
   V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames)        \
   V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset)     \
   V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset)           \
   V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset)                 \
   V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)                 \
   V(JSObject, observation_state, ObservationState)                             \
   V(Map, external_map, ExternalMap)                                            \
   V(Symbol, frozen_symbol, FrozenSymbol)                                       \
   V(SeededNumberDictionary, empty_slow_element_dictionary,                     \
-      EmptySlowElementDictionary)
+      EmptySlowElementDictionary)                                              \
+  V(Symbol, observed_symbol, ObservedSymbol)
 
 #define ROOT_LIST(V)                                  \
   STRONG_ROOT_LIST(V)                                 \
   V(StringTable, string_table, StringTable)
 
 #define INTERNALIZED_STRING_LIST(V)                                      \
   V(Array_string, "Array")                                               \
   V(Object_string, "Object")                                             \
   V(proto_string, "__proto__")                                           \
   V(StringImpl_string, "StringImpl")                                     \
@@ skipping 2885 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_