Add WrapUnique helper to wrap a raw pointer in a std::unique_ptr.

base/memory/ptr_util.h

+// Copyright 2015 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.
+
+#ifndef BASE_MEMORY_PTR_UTIL_H_
+#define BASE_MEMORY_PTR_UTIL_H_
+
+#include <memory>
+
+namespace base {
+
+// Helper to transfer ownership of a raw pointer to a std::unique_ptr<T>.
+// Note that std::unique_ptr<T> has very different semantics from
+// std::unique_ptr<T[]>: do not use this helper for array allocations.
+template <typename T>
+std::unique_ptr<T> WrapUnique(T* ptr) {
+  return std::unique_ptr<T>(ptr);
+}
+
+}  // namespace base
+
+#endif  // BASE_MEMORY_PTR_UTIL_H_