Allow custom deleters to opt out of self reset checks for scoped_ptr.

base/memory/scoped_ptr.h

Index: base/memory/scoped_ptr.h
diff --git a/base/memory/scoped_ptr.h b/base/memory/scoped_ptr.h
index 81b4a6239386cc3d556810aa1fbc6c0526de9b12..51ff68308a6d01f8c2c9370e565adcc8d51e72ce 100644
--- a/base/memory/scoped_ptr.h
+++ b/base/memory/scoped_ptr.h
@@ -184,6 +184,17 @@ template <typename T> struct IsNotRefCounted {
   };
 };
 
+template <typename T>
+struct ShouldAbortOnSelfReset {
+  template <typename U>
+  static NoType Test(const typename U::AllowSelfReset*);
+
+  template <typename U>
+  static YesType Test(...);
+
+  static const bool value = sizeof(Test<T>(0)) == sizeof(YesType);
+};
+
 // Minimal implementation of the core logic of scoped_ptr, suitable for
 // reuse in both scoped_ptr and its specializations.
 template <class T, class D>
@@ -222,8 +233,9 @@ class scoped_ptr_impl {
   }
 
   void reset(T* p) {
-    // This is a self-reset, which is no longer allowed: http://crbug.com/162971
-    if (p != nullptr && p == data_.ptr)
+    // This is a self-reset, which is no longer allowed for default deleters:
+    // https://crbug.com/162971
+    if (ShouldAbortOnSelfReset<D>::value && p != nullptr && p == data_.ptr)
       abort();
 
     // Note that running data_.ptr = p can lead to undefined behavior if