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 238 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)
-      : polymorphic_invoke_(&T::FunctionTraits::DoInvoke) {
+      : polymorphic_invoke_(&T::Invoker::DoInvoke) {
     invoker_storage_.swap(invoker_holder.invoker_storage_);
   }
 
 
 $if ARITY == 0 [[
   R Run(void) const {
 ]] $else [[
   R Run($for ARG ,
         [[const A$(ARG)& a$(ARG)]]) const {
 ]]
@@ skipping 12 matching lines @@
 
 ]]  $$ 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