Rewrite rtc::Bind using variadic templates.

webrtc/base/template_util.h

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 30 matching lines @@
 template<class T, size_t n> struct is_array<T[n]> : public true_type {};
 template<class T> struct is_array<T[]> : public true_type {};
 
 template <class T> struct is_non_const_reference : false_type {};
 template <class T> struct is_non_const_reference<T&> : true_type {};
 template <class T> struct is_non_const_reference<const T&> : false_type {};
 
 template <class T> struct is_void : false_type {};
 template <> struct is_void<void> : true_type {};
 
-template <class T>
-struct remove_reference {
-  typedef T type;
-};
-template <class T>
-struct remove_reference<T&> {
-  typedef T type;
-};
-template <class T>
-struct remove_reference<T&&> {
-  typedef T type;
+// Helper useful for converting a tuple to variadic template function
+// arguments.
+//
+// sequence_generator<3>::type will be sequence<0, 1, 2>.
+template <int...>
+struct sequence {};
+template <int N, int... S>
+struct sequence_generator : sequence_generator<N - 1, N - 1, S...> {};
+template <int... S>
+struct sequence_generator<0, S...> {
+  typedef sequence<S...> type;
 };
 
 namespace internal {
 
 // Types YesType and NoType are guaranteed such that sizeof(YesType) <
 // sizeof(NoType).
 typedef char YesType;
 
 struct NoType {
   YesType dummy[2];
@@ skipping 46 matching lines @@
 template <typename T>
 struct is_class
     : integral_constant<bool,
                         sizeof(internal::IsClassHelper::Test<T>(0)) ==
                             sizeof(internal::YesType)> {
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_TEMPLATE_UTIL_H_