Cleanup: Remove wstring methods from base::Pickle.

ipc/ipc_message_utils.h

 // Copyright (c) 2012 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.
 
 #ifndef IPC_IPC_MESSAGE_UTILS_H_
 #define IPC_IPC_MESSAGE_UTILS_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
@@ skipping 233 matching lines @@
     m->WriteString(p);
   }
   static bool Read(const Message* m, PickleIterator* iter,
                    param_type* r) {
     return iter->ReadString(r);
   }
   IPC_EXPORT static void Log(const param_type& p, std::string* l);
 };
 
 template <>
-struct ParamTraits<std::wstring> {
-  typedef std::wstring param_type;
-  static void Write(Message* m, const param_type& p) {
-    m->WriteWString(p);
-  }
-  static bool Read(const Message* m, PickleIterator* iter,
-                   param_type* r) {
-    return iter->ReadWString(r);
-  }
-  IPC_EXPORT static void Log(const param_type& p, std::string* l);
-};
-
-// If WCHAR_T_IS_UTF16 is defined, then string16 is a std::wstring so we don't
-// need this trait.
-#if !defined(WCHAR_T_IS_UTF16)
-template <>
 struct ParamTraits<base::string16> {
   typedef base::string16 param_type;
   static void Write(Message* m, const param_type& p) {
     m->WriteString16(p);
   }
   static bool Read(const Message* m, PickleIterator* iter,
                    param_type* r) {
     return iter->ReadString16(r);
   }
   IPC_EXPORT static void Log(const param_type& p, std::string* l);
 };
-#endif
 
 template <>
 struct IPC_EXPORT ParamTraits<std::vector<char> > {
   typedef std::vector<char> param_type;
   static void Write(Message* m, const param_type& p);
   static bool Read(const Message*, PickleIterator* iter, param_type* r);
   static void Log(const param_type& p, std::string* l);
 };
 
 template <>
@@ skipping 658 matching lines @@
   template<typename TA, typename TB, typename TC, typename TD, typename TE>
   static void WriteReplyParams(Message* reply, TA a, TB b, TC c, TD d, TE e) {
     ReplyParam p(a, b, c, d, e);
     WriteParam(reply, p);
   }
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_MESSAGE_UTILS_H_