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

Source/build/scripts/make_css_value_keywords.py

Index: Source/build/scripts/make_css_value_keywords.py
diff --git a/Source/build/scripts/make_css_value_keywords.py b/Source/build/scripts/make_css_value_keywords.py
index 49771f5defe13ab4db3109956e5cd76823566d6b..cfb8e4cb6cebbd03d8cb5117ae80322e83f210fc 100755
--- a/Source/build/scripts/make_css_value_keywords.py
+++ b/Source/build/scripts/make_css_value_keywords.py
@@ -168,7 +168,9 @@ class CSSValueKeywordsWriter(in_generator.Writer):
             '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]