Correct a comment in tuple.h that tripped me up.

base/tuple.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.
 
 // A Tuple is a generic templatized container, similar in concept to std::pair
 // and std::tuple.  The convenient MakeTuple() function takes any number of
 // arguments and will construct and return the appropriate Tuple object.  The
 // functions DispatchToMethod and DispatchToFunction take a function pointer or
 // instance and method pointer, and unpack a tuple into arguments to the call.
 //
@@ skipping 76 matching lines @@
 template <> struct MakeIndexSequenceImpl<11> {
   using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10>;
 };
 template <> struct MakeIndexSequenceImpl<12> {
   using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10,11>;
 };
 template <> struct MakeIndexSequenceImpl<13> {
   using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10,11,12>;
 };
 
-#else  // defined(WIN) && defined(_PREFAST_)
+#else  // defined(OS_WIN) && defined(_PREFAST_)
 
 template <size_t... Ns>
 struct MakeIndexSequenceImpl<0, Ns...> {
   using Type = IndexSequence<Ns...>;
 };
 
 template <size_t N, size_t... Ns>
 struct MakeIndexSequenceImpl<N, Ns...>
     : MakeIndexSequenceImpl<N - 1, N - 1, Ns...> {};
 
-#endif  // defined(WIN) && defined(_PREFAST_)
+#endif  // defined(OS_WIN) && defined(_PREFAST_)
 
 template <size_t N>
 using MakeIndexSequence = typename MakeIndexSequenceImpl<N>::Type;
 
 // Tuple -----------------------------------------------------------------------
 //
 // This set of classes is useful for bundling 0 or more heterogeneous data types
 // into a single variable.  The advantage of this is that it greatly simplifies
 // function objects that need to take an arbitrary number of parameters; see
 // RunnableMethod and IPC::MessageWithTuple.
@@ skipping 91 matching lines @@
                              const Tuple<InTs...>& in,
                              Tuple<OutTs...>* out) {
   DispatchToMethodImpl(obj, method, in, out,
                        MakeIndexSequence<sizeof...(InTs)>(),
                        MakeIndexSequence<sizeof...(OutTs)>());
 }
 
 }  // namespace base
 
 #endif  // BASE_TUPLE_H_