Improve JSON stringifier's escape check.

src/preparser.cc

 // 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 1619 matching lines @@
 #undef CHECK_OK
 
 
 // This function reads an identifier and determines whether or not it
 // is 'get' or 'set'.
 PreParser::Identifier PreParser::ParseIdentifierNameOrGetOrSet(bool* is_get,
                                                                bool* is_set,
                                                                bool* ok) {
   Identifier result = ParseIdentifierName(ok);
   if (!*ok) return Identifier::Default();
-  if (scanner_->is_literal_ascii() &&
+  if (scanner_->is_literal_printable_ascii() &&
       scanner_->literal_length() == 3) {
     const char* token = scanner_->literal_ascii_string().start();
     *is_get = strncmp(token, "get", 3) == 0;
     *is_set = !*is_get && strncmp(token, "set", 3) == 0;
   }
   return result;
 }
 
 bool PreParser::peek_any_identifier() {
   i::Token::Value next = peek();
@@ skipping 129 matching lines @@
       backing_store_.Add(static_cast<byte>((ascii_length >> 14) | 0x80u));
     }
     backing_store_.Add(static_cast<byte>((ascii_length >> 7) | 0x80u));
   }
   backing_store_.Add(static_cast<byte>(ascii_length & 0x7f));
 
   backing_store_.AddBlock(bytes);
   return backing_store_.EndSequence().start();
 }
 } }  // v8::preparser