From 483b62a868c78f04247a61bab254844750b79bfa Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Thu, 30 Aug 2018 17:16:53 +0200
Subject: [Revert] Remove base::internal::PassingTraits

This simplification doesn't work on MSVC 2017 due to some MSVC bug,
so stick with the old version for now.

Reverting https://chromium-review.googlesource.com/1118061

Change-Id: I3dff6075f9cc37dcc39c26b4f24de0501c8a362f
Reviewed-by: Michal Klocek <michal.klocek@qt.io>
---
 chromium/base/bind_internal.h     |  5 +++--
 chromium/base/callback.h          |  4 ++--
 chromium/base/callback_internal.h | 15 ++++++++++++++-
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/chromium/base/bind_internal.h b/chromium/base/bind_internal.h
index 02c06b7b584..18f3bfa0a32 100644
--- a/chromium/base/bind_internal.h
+++ b/chromium/base/bind_internal.h
@@ -630,7 +630,7 @@ struct Invoker;
 template <typename StorageType, typename R, typename... UnboundArgs>
 struct Invoker<StorageType, R(UnboundArgs...)> {
   static R RunOnce(BindStateBase* base,
-                   PassingType<UnboundArgs>... unbound_args) {
+                   PassingTraitsType<UnboundArgs>... unbound_args) {
     // Local references to make debugger stepping easier. If in a debugger,
     // you really want to warp ahead and step through the
     // InvokeHelper<>::MakeItSo() call below.
@@ -643,7 +643,8 @@ struct Invoker<StorageType, R(UnboundArgs...)> {
                    std::forward<UnboundArgs>(unbound_args)...);
   }
 
-  static R Run(BindStateBase* base, PassingType<UnboundArgs>... unbound_args) {
+  static R Run(BindStateBase* base,
+               PassingTraitsType<UnboundArgs>... unbound_args) {
     // Local references to make debugger stepping easier. If in a debugger,
     // you really want to warp ahead and step through the
     // InvokeHelper<>::MakeItSo() call below.
diff --git a/chromium/base/callback.h b/chromium/base/callback.h
index 1427faaaea9..fde82605f25 100644
--- a/chromium/base/callback.h
+++ b/chromium/base/callback.h
@@ -58,7 +58,7 @@ class OnceCallback<R(Args...)> : public internal::CallbackBase {
  public:
   using RunType = R(Args...);
   using PolymorphicInvoke = R (*)(internal::BindStateBase*,
-                                  internal::PassingType<Args>...);
+                                  internal::PassingTraitsType<Args>...);
 
   constexpr OnceCallback() = default;
   OnceCallback(std::nullptr_t) = delete;
@@ -104,7 +104,7 @@ class RepeatingCallback<R(Args...)> : public internal::CallbackBaseCopyable {
  public:
   using RunType = R(Args...);
   using PolymorphicInvoke = R (*)(internal::BindStateBase*,
-                                  internal::PassingType<Args>...);
+                                  internal::PassingTraitsType<Args>...);
 
   constexpr RepeatingCallback() = default;
   RepeatingCallback(std::nullptr_t) = delete;
diff --git a/chromium/base/callback_internal.h b/chromium/base/callback_internal.h
index fdfdf7f8175..cbdb0c724c7 100644
--- a/chromium/base/callback_internal.h
+++ b/chromium/base/callback_internal.h
@@ -36,8 +36,21 @@ struct BindStateBaseRefCountTraits {
   static void Destruct(const BindStateBase*);
 };
 
+template <typename T, bool IsScalar = std::is_scalar<T>::value>
+struct PassingTraits;
+
+template <typename T>
+struct PassingTraits<T, false> {
+  using Type = T&&;
+};
+
+template <typename T>
+struct PassingTraits<T, true> {
+  using Type = T;
+};
+
 template <typename T>
-using PassingType = std::conditional_t<std::is_scalar<T>::value, T, T&&>;
+using PassingTraitsType = typename PassingTraits<T>::Type;
 
 // BindStateBase is used to provide an opaque handle that the Callback
 // class can use to represent a function object with bound arguments.  It
-- 
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