Invalidate cross-thread persistents on heap termination.

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 526 matching lines @@
 
     void collectAndReportMarkSweepStats() const;
     void reportMarkSweepStats(const char* statsName, const ClassAgeCountsMap&) const;
 #endif
 
     void pushThreadLocalWeakCallback(void*, WeakCallback);
     bool popAndInvokeThreadLocalWeakCallback(Visitor*);
     void threadLocalWeakProcessing();
 
     size_t objectPayloadSizeForTesting();
-    void prepareHeapForTermination();
 
     // Register the pre-finalizer for the |self| object. This method is normally
     // called in the constructor of the |self| object. The class T must have
     // USING_PRE_FINALIZER().
     template<typename T>
     void registerPreFinalizer(T* self)
     {
         static_assert(sizeof(&T::invokePreFinalizer) > 0, "USING_PRE_FINALIZER(T) must be defined.");
         ASSERT(checkThread());
         ASSERT(!sweepForbidden());
@@ skipping 140 matching lines @@
     // When ThreadState is detaching from non-main thread its
     // heap is expected to be empty (because it is going away).
     // Perform registered cleanup tasks and garbage collection
     // to sweep away any objects that are left on this heap.
     // We assert that nothing must remain after this cleanup.
     // If assertion does not hold we crash as we are potentially
     // in the dangling pointer situation.
     void cleanup();
     void cleanupPages();
 
+    void prepareForThreadStateTermination();
+
     void invokePreFinalizers();
 
     void takeSnapshot(SnapshotType);
 #if ENABLE(GC_PROFILING)
     void snapshotFreeList();
 #endif
     void clearHeapAges();
     int heapIndexOfVectorHeapLeastRecentlyExpanded(int beginHeapIndex, int endHeapIndex);
 
     using InterruptorVector = Vector<OwnPtr<Interruptor>>;
@@ skipping 84 matching lines @@
 };
 
 template<> class ThreadStateFor<AnyThread> {
 public:
     static ThreadState* state() { return ThreadState::current(); }
 };
 
 } // namespace blink
 
 #endif // ThreadState_h