Callback: Replumb the type-inference.

base/callback.h.pump

 $$ This is a pump file for generating file templates.  Pump is a python
 $$ script that is part of the Google Test suite of utilities.  Description
 $$ can be found here:
 $$
 $$ http://code.google.com/p/googletest/wiki/PumpManual
 $$
 
 $var MAX_ARITY = 6
 
 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
@@ skipping 208 matching lines @@
 // First, we forward declare the Callback class template. This informs the
 // compiler that the template only has 1 type parameter which is the function
 // signature that the Callback is representing.
 //
 // After this, create template specializations for 0-$(MAX_ARITY) parameters. Note that
 // even though the template typelist grows, the specialization still
 // only has one type: the function signature.
 template <typename Sig>
 class Callback;
 
+
 $range ARITY 0..MAX_ARITY
 $for ARITY [[
 $range ARG 1..ARITY
 
 $if ARITY == 0 [[
 template <typename R>
 class Callback<R(void)> : public internal::CallbackBase {
 ]] $else [[
 template <typename R, $for ARG , [[typename A$(ARG)]]>
 class Callback<R($for ARG , [[A$(ARG)]])> : public internal::CallbackBase {
@@ skipping 10 matching lines @@
   // We pass InvokerStorageHolder by const ref to avoid incurring an
   // unnecessary AddRef/Unref pair even though we will modify the object.
   // We cannot use a normal reference because the compiler will warn
   // since this is often used on a return value, which is a temporary.
   //
   // Note that this constructor CANNOT be explicit, and that Bind() CANNOT
   // return the exact Callback<> type.  See base/bind.h for details.
   template <typename T>
   Callback(const internal::InvokerStorageHolder<T>& invoker_holder)
       : CallbackBase(
-          reinterpret_cast<InvokeFuncStorage>(&T::FunctionTraits::DoInvoke),
+          reinterpret_cast<InvokeFuncStorage>(&T::Invoker::DoInvoke),
           &invoker_holder.invoker_storage_) {
   }
 
   R Run($for ARG ,
         [[const A$(ARG)& a$(ARG)]]) const {
     PolymorphicInvoke f =
         reinterpret_cast<PolymorphicInvoke>(polymorphic_invoke_);
 
     return f(invoker_storage_.get()[[]]
 $if ARITY != 0 [[, ]]
 $for ARG ,
              [[a$(ARG)]]);
   }
 };
 
 
 ]]  $$ for ARITY
 
 // Syntactic sugar to make Callbacks<void(void)> easier to declare since it
 // will be used in a lot of APIs with delayed execution.
 typedef Callback<void(void)> Closure;
 
 }  // namespace base
 
 #endif  // BASE_CALLBACK_H