diff -r 000000000000 -r 6474c204b198 security/sandbox/chromium/base/callback_internal.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/sandbox/chromium/base/callback_internal.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,38 @@
+// 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.
+
+#include "base/callback_internal.h"
+
+#include "base/logging.h"
+
+namespace base {
+namespace internal {
+
+bool CallbackBase::is_null() const {
+  return bind_state_.get() == NULL;
+}
+
+void CallbackBase::Reset() {
+  polymorphic_invoke_ = NULL;
+  // NULL the bind_state_ last, since it may be holding the last ref to whatever
+  // object owns us, and we may be deleted after that.
+  bind_state_ = NULL;
+}
+
+bool CallbackBase::Equals(const CallbackBase& other) const {
+  return bind_state_.get() == other.bind_state_.get() &&
+         polymorphic_invoke_ == other.polymorphic_invoke_;
+}
+
+CallbackBase::CallbackBase(BindStateBase* bind_state)
+    : bind_state_(bind_state),
+      polymorphic_invoke_(NULL) {
+  DCHECK(!bind_state_.get() || bind_state_->HasOneRef());
+}
+
+CallbackBase::~CallbackBase() {
+}
+
+}  // namespace internal
+}  // namespace base