Worker: Introduce an observation mechanism for WorkerThread termination

third_party/WebKit/Source/platform/CrossThreadCopier.h

 /*
  * Copyright (C) 2009, 2010 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 142 matching lines @@
         return pointer; // This is in fact a move.
     }
 };
 
 template<typename T>
 struct CrossThreadCopier<CrossThreadPersistent<T>> : public CrossThreadCopierPassThrough<CrossThreadPersistent<T>> {
     STATIC_ONLY(CrossThreadCopier);
 };
 
 template<typename T>
+struct CrossThreadCopier<CrossThreadWeakPersistent<T>> : public CrossThreadCopierPassThrough<CrossThreadWeakPersistent<T>> {
+    STATIC_ONLY(CrossThreadCopier);
+};
+
+template<typename T>
 struct CrossThreadCopier<WeakPtr<T>> : public CrossThreadCopierPassThrough<WeakPtr<T>> {
     STATIC_ONLY(CrossThreadCopier);
 };
 
 template <typename T>
 struct CrossThreadCopier<WTF::PassedWrapper<T>> {
     STATIC_ONLY(CrossThreadCopier);
     using Type = WTF::PassedWrapper<typename CrossThreadCopier<T>::Type>;
     static Type copy(WTF::PassedWrapper<T>&& value) { return passed(CrossThreadCopier<T>::copy(value.moveOut())); }
 };
@@ skipping 81 matching lines @@
 AllowCrossThreadAccessWrapper<T*> AllowCrossThreadAccess(T* value)
 {
     static_assert(!IsGarbageCollectedType<T>::value, "Use wrapCrossThreadPersistent() instead for garbage-collected pointers");
     static_assert(!WTF::IsSubclassOfTemplate<T, ThreadSafeRefCounted>::value, "Use PassRefPtr<T> instead for ThreadSafeRefCounted");
     return AllowCrossThreadAccessWrapper<T*>(value);
 }
 
 } // namespace blink
 
 #endif // CrossThreadCopier_h