Allow passing WeakPtr across threads without AllowCrossThreadAccess()

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 141 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<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())); }
 };
 
 template<typename T>
 struct CrossThreadCopier<CrossThreadWeakPersistentThisPointer<T>> : public CrossThreadCopierPassThrough<CrossThreadWeakPersistentThisPointer<T>> {
     STATIC_ONLY(CrossThreadCopier);
@@ skipping 38 matching lines @@
 struct CrossThreadCopier<Member<T>> {
     STATIC_ONLY(CrossThreadCopier);
     static_assert(IsGarbageCollectedType<T>::value, "T must be a garbage-collected type.");
     typedef T* Type;
     static Type copy(const Member<T>& ptr)
     {
         return ptr;
     }
 };
 
-// |T| is |C*| or |const WeakPtr<C>&|.
+// |T| is a pointer type.
 template <typename T>
 struct AllowCrossThreadAccessWrapper {
     STACK_ALLOCATED();
 public:
     T value() const { return m_value; }
 private:
-    // Only constructible from AllowCrossThreadAccess().
+    // Only constructible from AllowCrossThreadAccess*().
     explicit AllowCrossThreadAccessWrapper(T value) : m_value(value) { }
     template <typename U>
     friend AllowCrossThreadAccessWrapper<U*> AllowCrossThreadAccess(U*);
-    template <typename U>
-    friend AllowCrossThreadAccessWrapper<const WeakPtr<U>&> AllowCrossThreadAccess(const WeakPtr<U>&);
 
     // This raw pointer is safe since AllowCrossThreadAccessWrapper is
     // always stack-allocated. Ideally this should be Member<T> if T is
     // garbage-collected and T* otherwise, but we don't want to introduce
     // another template magic just for distinguishing Member<T> from T*.
     // From the perspective of GC, T* always works correctly.
     GC_PLUGIN_IGNORE("")
     T m_value;
 };
 
 template <typename T>
 struct CrossThreadCopier<AllowCrossThreadAccessWrapper<T>> {
     STATIC_ONLY(CrossThreadCopier);
     typedef T Type;
     static Type copy(const AllowCrossThreadAccessWrapper<T>& wrapper) { return wrapper.value(); }
 };
 
 template <typename T>
 AllowCrossThreadAccessWrapper<T*> AllowCrossThreadAccess(T* value)
 {
     static_assert(!blink::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);
 }
 
-template <typename T>
-AllowCrossThreadAccessWrapper<const WeakPtr<T>&> AllowCrossThreadAccess(const WeakPtr<T>& value)
-{
-    return AllowCrossThreadAccessWrapper<const WeakPtr<T>&>(value);
-}
-
 } // namespace blink
 
 #endif // CrossThreadCopier_h