[heap] Prevent leakage of GCCallbacksScope outside of heap.

src/heap/heap.cc

 // 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.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 729 matching lines @@
       int pos = code->SourcePosition(pc);
       elements->set(j + 2, Smi::FromInt(pos));
     }
   }
   // We must not compact the weak fixed list here, as we may be in the middle
   // of writing to it, when the GC triggered. Instead, we reset the root value.
   set_weak_stack_trace_list(Smi::FromInt(0));
 }
 
 
+class GCCallbacksScope {
+ public:
+  explicit GCCallbacksScope(Heap* heap) : heap_(heap) {
+    heap_->gc_callbacks_depth_++;
+  }
+  ~GCCallbacksScope() { heap_->gc_callbacks_depth_--; }
+
+  bool CheckReenter() { return heap_->gc_callbacks_depth_ == 1; }
+
+ private:
+  Heap* heap_;
+};
+
+
 void Heap::HandleGCRequest() {
   if (incremental_marking()->request_type() ==
       IncrementalMarking::COMPLETE_MARKING) {
     CollectAllGarbage(current_gc_flags_, "GC interrupt",
                       current_gc_callback_flags_);
     return;
   }
   DCHECK(FLAG_overapproximate_weak_closure);
   if (!incremental_marking()->weak_closure_was_overapproximated()) {
     OverApproximateWeakClosure("GC interrupt");
@@ skipping 5911 matching lines @@
     *object_sub_type = "CODE_AGE/" #name;                              \
     return true;
     CODE_AGE_LIST_COMPLETE(COMPARE_AND_RETURN_NAME)
 #undef COMPARE_AND_RETURN_NAME
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8