Cleanup latin-1 conversion check in regexp engine

src/unicode.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 122 matching lines @@
   }
 };
 
 class Latin1 {
  public:
 #ifndef ENABLE_LATIN_1
   static const unsigned kMaxChar = 0x7f;
 #else
   static const unsigned kMaxChar = 0xff;
 #endif
+  static inline bool NonLatin1CanBeConvertedToLatin1(uint16_t);
 };
 
 class Utf8 {
  public:
   static inline uchar Length(uchar chr, int previous);
   static inline unsigned Encode(
       char* out, uchar c, int previous);
   static uchar CalculateValue(const byte* str,
                               unsigned length,
                               unsigned* cursor);
@@ skipping 111 matching lines @@
   static const int kMaxWidth = 1;
   static int Convert(uchar c,
                      uchar n,
                      uchar* result,
                      bool* allow_caching_ptr);
 };
 
 }  // namespace unibrow
 
 #endif  // V8_UNICODE_H_