Disallow off-heap containers containing raw on-heap pointers.

third_party/WebKit/Source/wtf/LinkedHashSet.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2011, Benjamin Poulain <ikipou@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 580 matching lines @@
     Superclass::operator++();
     return *this;
   }
 
   // Postfix ++ and -- intentionally omitted.
 
   template <typename T, typename U, typename V, typename W>
   friend class LinkedHashSet;
 };
 
-template <typename T, typename U, typename V, typename W>
-inline LinkedHashSet<T, U, V, W>::LinkedHashSet() {}
+template <typename T, typename U, typename V, typename Allocator>
+inline LinkedHashSet<T, U, V, Allocator>::LinkedHashSet() {
+  static_assert(
+      Allocator::isGarbageCollected ||
+          !IsPointerToGarbageCollectedType<T>::value,
+      "Cannot put raw pointers to garbage-collected classes into "
+      "an off-heap LinkedHashSet. Use HeapLinkedHashSet<Member<T>> instead.");
+}
 
 template <typename T, typename U, typename V, typename W>
 inline LinkedHashSet<T, U, V, W>::LinkedHashSet(const LinkedHashSet& other)
     : m_anchor() {
   const_iterator end = other.end();
   for (const_iterator it = other.begin(); it != end; ++it)
     add(*it);
 }
 
 template <typename T, typename U, typename V, typename W>
@@ skipping 255 matching lines @@
   swap(static_cast<Base&>(a), static_cast<Base&>(b));
   swap(a.m_value, b.m_value);
   Allocator::leaveGCForbiddenScope();
 }
 
 }  // namespace WTF
 
 using WTF::LinkedHashSet;
 
 #endif /* WTF_LinkedHashSet_h */