Simplify createCrossThreadTask()

third_party/WebKit/Source/wtf/Functional.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 106 matching lines @@
 // provide a unified interface for calling that function.
 template <typename>
 class FunctionWrapper;
 
 // Bound static functions:
 template <typename R, typename... Parameters>
 class FunctionWrapper<R(*)(Parameters...)> {
     DISALLOW_NEW();
 public:
     typedef R ResultType;
+    static const size_t numberOfArguments = sizeof...(Parameters);
 
     explicit FunctionWrapper(R(*function)(Parameters...))
         : m_function(function)
     {
     }
 
     template <typename... IncomingParameters>
     R operator()(IncomingParameters&&... parameters)
     {
         return m_function(std::forward<IncomingParameters>(parameters)...);
     }
 
 private:
     R(*m_function)(Parameters...);
 };
 
 // Bound member functions:
 
 template <typename R, typename C, typename... Parameters>
 class FunctionWrapper<R(C::*)(Parameters...)> {
     DISALLOW_NEW();
 public:
     typedef R ResultType;
+    // + 1 is for |this| as an argument.
+    static const size_t numberOfArguments = sizeof...(Parameters) + 1;
 
     explicit FunctionWrapper(R(C::*function)(Parameters...))
         : m_function(function)
     {
     }
 
     template <typename... IncomingParameters>
     R operator()(C* c, IncomingParameters&&... parameters)
     {
         return (c->*m_function)(std::forward<IncomingParameters>(parameters)...);
@@ skipping 177 matching lines @@
 
 } // namespace WTF
 
 using WTF::passed;
 using WTF::Function;
 using WTF::bind;
 using WTF::SameThreadClosure;
 using WTF::CrossThreadClosure;
 
 #endif // WTF_Functional_h