styleguide: Allow enable_if, conditional, and other type_traits.

base/bind_internal.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 BASE_BIND_INTERNAL_H_
 #define BASE_BIND_INTERNAL_H_
 
+#include <type_traits>
+
 #include "base/bind_helpers.h"
 #include "base/callback_internal.h"
 #include "base/memory/raw_scoped_refptr_mismatch_checker.h"
 #include "base/memory/weak_ptr.h"
 #include "base/template_util.h"
 #include "base/tuple.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include "base/bind_internal_win.h"
@@ skipping 52 matching lines @@
 // Implementation note: This non-specialized case handles zero-arity case only.
 // Non-zero-arity cases should be handled by the specialization below.
 template <typename Sig>
 struct HasNonConstReferenceParam : false_type {};
 
 // Implementation note: Select true_type if the first parameter is a non-const
 // reference.  Otherwise, skip the first parameter and check rest of parameters
 // recursively.
 template <typename R, typename T, typename... Args>
 struct HasNonConstReferenceParam<R(T, Args...)>
-    : SelectType<is_non_const_reference<T>::value,
-                 true_type,
-                 HasNonConstReferenceParam<R(Args...)>>::Type {};
+    : std::conditional<is_non_const_reference<T>::value,
+                       true_type,
+                       HasNonConstReferenceParam<R(Args...)>>::type {};
 
 // HasRefCountedTypeAsRawPtr selects true_type when any of the |Args| is a raw
 // pointer to a RefCounted type.
 // Implementation note: This non-specialized case handles zero-arity case only.
 // Non-zero-arity cases should be handled by the specialization below.
 template <typename... Args>
 struct HasRefCountedTypeAsRawPtr : false_type {};
 
 // Implementation note: Select true_type if the first parameter is a raw pointer
 // to a RefCounted type. Otherwise, skip the first parameter and check rest of
 // parameters recursively.
 template <typename T, typename... Args>
 struct HasRefCountedTypeAsRawPtr<T, Args...>
-    : SelectType<NeedsScopedRefptrButGetsRawPtr<T>::value,
-                 true_type,
-                 HasRefCountedTypeAsRawPtr<Args...>>::Type {};
+    : std::conditional<NeedsScopedRefptrButGetsRawPtr<T>::value,
+                       true_type,
+                       HasRefCountedTypeAsRawPtr<Args...>>::type {};
 
 // BindsArrayToFirstArg selects true_type when |is_method| is true and the first
 // item of |Args| is an array type.
 // Implementation note: This non-specialized case handles !is_method case and
 // zero-arity case only.  Other cases should be handled by the specialization
 // below.
 template <bool is_method, typename... Args>
 struct BindsArrayToFirstArg : false_type {};
 
 template <typename T, typename... Args>
@@ skipping 304 matching lines @@
 
   static void Destroy(BindStateBase* self) {
     delete static_cast<BindState*>(self);
   }
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_BIND_INTERNAL_H_