Verify that a new heap page isn't also marked as being off heap.

third_party/WebKit/Source/platform/heap/ThreadState.h

 /*
  * Copyright (C) 2013 Google Inc. 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
@@ skipping 361 matching lines @@
     Vector<size_t> liveSize;
     Vector<size_t> deadSize;
   };
 
   size_t objectPayloadSizeForTesting();
 
   void shouldFlushHeapDoesNotContainCache() {
     m_shouldFlushHeapDoesNotContainCache = true;
   }
 
+#if DCHECK_IS_ON()
+  bool isAddressInHeapDoesNotContainCache(Address);
+#endif
+
   void registerTraceDOMWrappers(
       v8::Isolate* isolate,
       void (*traceDOMWrappers)(v8::Isolate*, Visitor*),
       void (*invalidateDeadObjectsInWrappersMarkingDeque)(v8::Isolate*),
       void (*performCleanup)(v8::Isolate*)) {
     m_isolate = isolate;
     DCHECK(!m_isolate || traceDOMWrappers);
     DCHECK(!m_isolate || invalidateDeadObjectsInWrappersMarkingDeque);
     DCHECK(!m_isolate || performCleanup);
     m_traceDOMWrappers = traceDOMWrappers;
@@ skipping 305 matching lines @@
 class ThreadStateFor<AnyThread> {
   STATIC_ONLY(ThreadStateFor);
 
  public:
   static ThreadState* state() { return ThreadState::current(); }
 };
 
 }  // namespace blink
 
 #endif  // ThreadState_h