Revert of Clang plugin to check that unstable types are not used in IPC.

ipc/ipc_message_utils.h

Index: ipc/ipc_message_utils.h
diff --git a/ipc/ipc_message_utils.h b/ipc/ipc_message_utils.h
index 9369f023f4d7b6a69baaa7b03a7948b1c18eaafc..d92d8335f1a2cddee3d3ee487cd551dba8b20081 100644
--- a/ipc/ipc_message_utils.h
+++ b/ipc/ipc_message_utils.h
@@ -76,26 +76,12 @@
 struct NoParams {
 };
 
-// Specializations are checked by 'IPC checker' part of find-bad-constructs
-// Clang plugin (see WriteParam() below for the details).
-template <typename... Ts>
-struct CheckedTuple {
-  typedef std::tuple<Ts...> Tuple;
-};
-
 template <class P>
 static inline void GetParamSize(base::PickleSizer* sizer, const P& p) {
   typedef typename SimilarTypeTraits<P>::Type Type;
   ParamTraits<Type>::GetSize(sizer, static_cast<const Type&>(p));
 }
 
-// This function is checked by 'IPC checker' part of find-bad-constructs
-// Clang plugin to make it's not called on the following types:
-// 1. long / unsigned long (but not typedefs to)
-// 2. intmax_t, uintmax_t, intptr_t, uintptr_t, wint_t,
-//    size_t, rsize_t, ssize_t, ptrdiff_t, dev_t, off_t, clock_t,
-//    time_t, suseconds_t (including typedefs to)
-// 3. Any template referencing types above (e.g. std::vector<size_t>)
 template <class P>
 static inline void WriteParam(base::Pickle* m, const P& p) {
   typedef typename SimilarTypeTraits<P>::Type Type;