Support CrossThreadWeakPersistent PostTask on per thread heap enabled thread

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef Persistent_h
 #define Persistent_h
 
 #include "platform/heap/Heap.h"
 #include "platform/heap/Member.h"
 #include "platform/heap/PersistentNode.h"
@@ skipping 748 matching lines @@
 } // namespace WTF
 
 namespace base {
 
 template <typename T>
 struct IsWeakReceiver<blink::WeakPersistent<T>> : std::true_type {};
 
 template <typename T>
 struct IsWeakReceiver<blink::CrossThreadWeakPersistent<T>> : std::true_type {};
 
+template <typename T>
+struct BindUnwrapTraits<blink::CrossThreadWeakPersistent<T>> {
+    static blink::CrossThreadPersistent<T> Unwrap(const blink::CrossThreadWeakPersistent<T>& wrapped)
+    {
+        blink::CrossThreadPersistentRegion::LockScope persistentLock(blink::ProcessHeap::crossThreadPersistentRegion());
+        return blink::CrossThreadPersistent<T>(wrapped.get());
+    }
+};
+
 }
 
 #endif // Persistent_h