Upon clearing, release PersistentNode of cross-thread-persistent also.

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

 /*
  * Copyright (C) 2014 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 197 matching lines @@
         if (crossThreadnessConfiguration == CrossThreadPersistentConfiguration)
             releaseStore(reinterpret_cast<void* volatile*>(&m_raw), ptr);
         else
             m_raw = ptr;
         checkPointer();
         if (m_raw) {
             if (!m_persistentNode)
                 initialize();
             return;
         }
-        if (m_persistentNode && crossThreadnessConfiguration != CrossThreadPersistentConfiguration)
-            uninitialize();
+        uninitialize();
     }
 
     NO_LAZY_SWEEP_SANITIZE_ADDRESS
     void initialize()
     {
         ASSERT(!m_persistentNode);
         if (!m_raw)
             return;
 
         TraceCallback traceCallback = TraceMethodDelegate<PersistentBase<T, weaknessConfiguration, crossThreadnessConfiguration>, &PersistentBase<T, weaknessConfiguration, crossThreadnessConfiguration>::trace>::trampoline;
@@ skipping 984 matching lines @@
     // into it.
     //
     // TODO(sof): remove this hack once wtf/Functional.h can also work with a type like
     // CrossThreadWeakPersistent<>.
     static WeakPtr<T> unwrap(const StorageType& value) { return WeakPtr<T>(WeakReference<T>::create(value.get())); }
 };
 
 } // namespace WTF
 
 #endif