Do Perfect Forwarding from base::Bind to BindState storage

base/bind.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_H_
 #define BASE_BIND_H_
 
 #include "base/bind_internal.h"
 #include "base/callback_internal.h"

[danakj, 2016/01/28 23:01:00]

Should this be removed? (bind_internal.h still uses and includes it, but this
file isn't using anything directly from there now is it?)

[tzik, 2016/02/01 15:00:16]

Done.

 
 // -----------------------------------------------------------------------------
 // Usage documentation
 // -----------------------------------------------------------------------------
 //
 // See base/callback.h for documentation.
 //
 //
 // -----------------------------------------------------------------------------
 // Implementation notes
@@ skipping 25 matching lines @@
 // feels a little nicer to have the asserts here so people do not need to crack
 // open bind_internal.h.  On the other hand, it makes Bind() harder to read.
 
 namespace base {
 
 template <typename Functor, typename... Args>
 base::Callback<
     typename internal::BindState<
         typename internal::FunctorTraits<Functor>::RunnableType,
         typename internal::FunctorTraits<Functor>::RunType,
-        typename internal::CallbackParamTraits<Args>::StorageType...>
-            ::UnboundRunType>
-Bind(Functor functor, const Args&... args) {
+        typename std::decay<Args>::type...>::UnboundRunType>
+Bind(Functor functor, Args&&... args) {
   // Type aliases for how to store and run the functor.
   using RunnableType = typename internal::FunctorTraits<Functor>::RunnableType;
   using RunType = typename internal::FunctorTraits<Functor>::RunType;
 
   // Use RunnableType::RunType instead of RunType above because our
   // checks below for bound references need to know what the actual
   // functor is going to interpret the argument as.
   using BoundRunType = typename RunnableType::RunType;
 
   using BoundArgs =
@@ skipping 14 matching lines @@
   // a scoped_refptr because BindState<> itself takes care of AddRef() for
   // methods. We also disallow binding of an array as the method's target
   // object.
   static_assert(!internal::BindsArrayToFirstArg<is_method, Args...>::value,
                 "first bound argument to method cannot be array");
   static_assert(
       !internal::HasRefCountedParamAsRawPtr<is_method, Args...>::value,
       "a parameter is a refcounted type and needs scoped_refptr");
 
   using BindState = internal::BindState<
-      RunnableType, RunType,
-      typename internal::CallbackParamTraits<Args>::StorageType...>;
+      RunnableType, RunType, typename std::decay<Args>::type...>;
 
   return Callback<typename BindState::UnboundRunType>(
-      new BindState(internal::MakeRunnable(functor), args...));
+      new BindState(internal::MakeRunnable(functor),
+                    std::forward<Args>(args)...));
 }
 
 }  // namespace base
 
 #endif  // BASE_BIND_H_