Switch from nonstd::unique_ptr to std::unique_ptr.

third_party/base/template_util.h

-// Copyright (c) 2011 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 PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_
-#define PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_
-
-#include <cstddef>  // For size_t.
-
-namespace pdfium {
-namespace base {
-
-template<class T, T v>
-struct integral_constant {
-  static const T value = v;
-  typedef T value_type;
-  typedef integral_constant<T, v> type;
-};
-
-typedef integral_constant<bool, true> true_type;
-typedef integral_constant<bool, false> false_type;
-
-template <class T, class U> struct is_same : public false_type {};
-template <class T>
-struct is_same<T, T> : true_type {};
-
-template<bool B, class T = void>
-struct enable_if {};
-
-template<class T>
-struct enable_if<true, T> { typedef T type; };
-
-namespace internal {
-
-// Types YesType and NoType are guaranteed such that sizeof(YesType) <
-// sizeof(NoType).
-typedef char YesType;
-
-struct NoType {
-  YesType dummy[2];
-};
-
-// This class is an implementation detail for is_convertible, and you
-// don't need to know how it works to use is_convertible. For those
-// who care: we declare two different functions, one whose argument is
-// of type To and one with a variadic argument list. We give them
-// return types of different size, so we can use sizeof to trick the
-// compiler into telling us which function it would have chosen if we
-// had called it with an argument of type From.  See Alexandrescu's
-// _Modern C++ Design_ for more details on this sort of trick.
-
-struct ConvertHelper {
-  template <typename To>
-  static YesType Test(To);
-
-  template <typename To>
-  static NoType Test(...);
-
-  template <typename From>
-  static From& Create();
-};
-
-}  // namespace internal
-
-// Inherits from true_type if From is convertible to To, false_type otherwise.
-//
-// Note that if the type is convertible, this will be a true_type REGARDLESS
-// of whether or not the conversion would emit a warning.
-template <typename From, typename To>
-struct is_convertible
-    : integral_constant<bool,
-                        sizeof(internal::ConvertHelper::Test<To>(
-                            internal::ConvertHelper::Create<From>())) ==
-                            sizeof(internal::YesType)> {};
-
-}  // namespace base
-}  // namespace pdfium
-
-#endif  // PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_