[MemUsage][BinarySize] More perfect hashes for CSS strings.

Source/build/scripts/make_css_value_keywords.py

 #!/usr/bin/env python
 
 import os.path
 import re
 import subprocess
 import sys
 
 from in_file import InFile
 import in_generator
 import license
@@ skipping 150 matching lines @@
             'license': license.license_for_generated_cpp(),
             'class_name': self.class_name,
             'value_keyword_strings': '\n'.join(map(lambda property: '    "%(name)s\\0"' % property, self._value_keywords)),
             'value_keyword_offsets': '\n'.join(map(lambda offset: '  %d,' % offset, keyword_offsets)),
             'value_keyword_to_enum_map': '\n'.join(map(lambda property: '%(name)s, %(enum_name)s' % property, self._value_keywords)),
             'ua_sheet_mode_values_keywords': '\n        '.join(map(self._case_value_keyword, self._value_keywords_with_mode('UASheet'))),
             'quirks_mode_values_keywords': '\n        '.join(map(self._case_value_keyword, self._value_keywords_with_mode('Quirks'))),
             'quirks_mode_or_ua_sheet_mode_values_keywords': '\n    '.join(map(self._case_value_keyword, self._value_keywords_with_mode('QuirksOrUASheet'))),
         }
         # FIXME: If we could depend on Python 2.7, we would use subprocess.check_output
-        gperf_args = [self.gperf_path, '--key-positions=*', '-D', '-n', '-s', '2']
+        gperf_args = [self.gperf_path, '--key-positions=*', '-P', '-n']
+        gperf_args.extend(['-m', '50'])  # Pick best of 50 attempts.
+        gperf_args.append('-D')  # Allow duplicate hashes -> More compact code.
         gperf = subprocess.Popen(gperf_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, universal_newlines=True)
         return gperf.communicate(gperf_input)[0]
 
 
 if __name__ == "__main__":
     in_generator.Maker(CSSValueKeywordsWriter).main(sys.argv)