Make sure that scoped_ptr<> cannot be used with ref-counted objects.

base/memory/scoped_ptr.h

 // Copyright (c) 2012 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.
 
 // Scopers help you manage ownership of a pointer, helping you easily manage the
 // a pointer within a scope, and automatically destroying the pointer at the
 // end of a scope.  There are two main classes you will use, which correspond
 // to the operators new/delete and new[]/delete[].
 //
 // Example usage (scoped_ptr):
@@ skipping 78 matching lines @@
 #pragma once
 
 // This is an implementation designed to match the anticipated future TR2
 // implementation of the scoped_ptr class, and its closely-related brethren,
 // scoped_array, scoped_ptr_malloc.
 
 #include <assert.h>
 #include <stddef.h>
 #include <stdlib.h>
 
+#include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/move.h"
+#include "base/template_util.h"
+
+namespace base {
+namespace subtle {
+class RefCountedBase;
+class RefCountedThreadSafeBase;
+}  // namespace subtle
+
+namespace internal {
+
+template <typename T> struct IsNotRefCounted {
+  enum {
+    value = !base::is_convertible<T*, base::subtle::RefCountedBase*>::value &&
+        !base::is_convertible<T*, base::subtle::RefCountedThreadSafeBase*>::
+            value
+  };
+};
+
+}  // namespace internal
+}  // namespace base
 
 // A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
 // automatically deletes the pointer it holds (if any).
 // That is, scoped_ptr<T> owns the T object that it points to.
 // Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to a T object.
 // Also like T*, scoped_ptr<T> is thread-compatible, and once you
 // dereference it, you get the thread safety guarantees of T.
 //
 // The size of a scoped_ptr is small:
 // sizeof(scoped_ptr<C>) == sizeof(C*)
 template <class C>
 class scoped_ptr {
   MOVE_ONLY_TYPE_FOR_CPP_03(scoped_ptr, RValue)
 
+  COMPILE_ASSERT(base::internal::IsNotRefCounted<C>::value,
+                 C_is_refcounted_type_and_needs_scoped_refptr);
+
  public:
 
   // The element type
   typedef C element_type;
 
   // Constructor.  Defaults to initializing with NULL.
   // There is no way to create an uninitialized scoped_ptr.
   // The input parameter must be allocated with new.
   explicit scoped_ptr(C* p = NULL) : ptr_(p) { }
 
@@ skipping 337 matching lines @@
 bool operator==(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p == b.get();
 }
 
 template<class C, class FP> inline
 bool operator!=(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p != b.get();
 }
 
 #endif  // BASE_MEMORY_SCOPED_PTR_H_