Oilpan: A thread that is not attached to Oilpan shouldn't create a CrossThreadPersistent

Source/platform/CrossThreadCopier.h

Index: Source/platform/CrossThreadCopier.h
diff --git a/Source/platform/CrossThreadCopier.h b/Source/platform/CrossThreadCopier.h
index a1f593e34c48edfa5132b28b7c595b0961e68641..866da405783f57f536381bdc1d240b81186a0208 100644
--- a/Source/platform/CrossThreadCopier.h
+++ b/Source/platform/CrossThreadCopier.h
@@ -41,6 +41,7 @@
 #include "wtf/RefPtr.h"
 #include "wtf/ThreadSafeRefCounted.h"
 #include "wtf/TypeTraits.h"
+#include "wtf/UnretainedPtr.h"
 
 namespace blink {
 
@@ -152,6 +153,14 @@ namespace blink {
         }
     };
 
+    template<typename T> struct CrossThreadCopierBase<false, false, true, UnretainedPtr<T> > {
+        typedef RawPtr<T> Type;
+        static Type copy(const Type& ptr)
+        {
+            return ptr;
+        }
+    };
+
     template<typename T> struct CrossThreadCopierBase<false, false, true, Member<T> > {
         typedef RawPtr<T> Type;
         static Type copy(const Member<T>& ptr)
@@ -174,6 +183,7 @@ namespace blink {
             || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, PassRefPtr>::Type, ThreadSafeRefCounted>::value,
         WTF::IsSubclassOfTemplate<typename WTF::RemovePointer<T>::Type, GarbageCollected>::value
             || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, RawPtr>::Type, GarbageCollected>::value
+            || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, UnretainedPtr>::Type, GarbageCollected>::value
             || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, Member>::Type, GarbageCollected>::value
             || WTF::IsSubclassOfTemplate<typename WTF::RemoveTemplate<T, WeakMember>::Type, GarbageCollected>::value,
         T> {