[OSX] Remove wide->NSString conversion

base/sys_string_conversions_mac.mm

 // 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.
 
 #include "base/sys_string_conversions.h"
 
 #import <Foundation/Foundation.h>
 
 #include <vector>
 
@@ skipping 148 matching lines @@
 NSString* SysUTF8ToNSString(const std::string& utf8) {
   return (NSString*)base::mac::CFTypeRefToNSObjectAutorelease(
       SysUTF8ToCFStringRef(utf8));
 }
 
 NSString* SysUTF16ToNSString(const string16& utf16) {
   return (NSString*)base::mac::CFTypeRefToNSObjectAutorelease(
       SysUTF16ToCFStringRef(utf16));
 }
 
-NSString* SysWideToNSString(const std::wstring& wide) {
-  return (NSString*)base::mac::CFTypeRefToNSObjectAutorelease(
-      SysWideToCFStringRef(wide));
-}
-
 std::string SysCFStringRefToUTF8(CFStringRef ref) {
   return CFStringToSTLStringWithEncodingT<std::string>(ref,
                                                        kNarrowStringEncoding);
 }
 
 string16 SysCFStringRefToUTF16(CFStringRef ref) {
   return CFStringToSTLStringWithEncodingT<string16>(ref,
                                                     kMediumStringEncoding);
 }
 
@@ skipping 14 matching lines @@
   return SysCFStringRefToUTF16(reinterpret_cast<CFStringRef>(nsstring));
 }
 
 std::wstring SysNSStringToWide(NSString* nsstring) {
   if (!nsstring)
     return std::wstring();
   return SysCFStringRefToWide(reinterpret_cast<CFStringRef>(nsstring));
 }
 
 }  // namespace base