Introduce a handle zapping setting, and enable it by default for release and debug

src/global-handles.cc

 // Copyright 2009 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 60 matching lines @@
     STATIC_ASSERT(static_cast<int>(NodeState::kMask) ==
                   Internals::kNodeStateMask);
     STATIC_ASSERT(WEAK == Internals::kNodeStateIsWeakValue);
     STATIC_ASSERT(NEAR_DEATH == Internals::kNodeStateIsNearDeathValue);
     STATIC_ASSERT(static_cast<int>(IsIndependent::kShift) ==
                   Internals::kNodeIsIndependentShift);
     STATIC_ASSERT(static_cast<int>(IsPartiallyDependent::kShift) ==
                   Internals::kNodeIsPartiallyDependentShift);
   }
 
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
   ~Node() {
     // TODO(1428): if it's a weak handle we should have invoked its callback.
     // Zap the values for eager trapping.
     object_ = reinterpret_cast<Object*>(kGlobalHandleZapValue);
     class_id_ = v8::HeapProfiler::kPersistentHandleNoClassId;
     index_ = 0;
     set_independent(false);
     set_partially_dependent(false);
     set_in_new_space_list(false);
     parameter_or_next_free_.next_free = NULL;
@@ skipping 18 matching lines @@
     set_partially_dependent(false);
     set_state(NORMAL);
     parameter_or_next_free_.parameter = NULL;
     weak_reference_callback_ = NULL;
     IncreaseBlockUses();
   }
 
   void Release() {
     ASSERT(state() != FREE);
     set_state(FREE);
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
     // Zap the values for eager trapping.
     object_ = reinterpret_cast<Object*>(kGlobalHandleZapValue);
     class_id_ = v8::HeapProfiler::kPersistentHandleNoClassId;
     set_independent(false);
     set_partially_dependent(false);
     weak_reference_callback_ = NULL;
 #endif
     DecreaseBlockUses();
   }
 
@@ skipping 870 matching lines @@
     }
   }
   object_group_connections_.Clear();
   object_group_connections_.Initialize(kObjectGroupConnectionsCapacity);
   retainer_infos_.Clear();
   implicit_ref_connections_.Clear();
 }
 
 
 } }  // namespace v8::internal