Added support for improvement_direction to relevant values, which is propogated to chartjson.

tools/perf/benchmarks/sunspider.py

Index: tools/perf/benchmarks/sunspider.py
diff --git a/tools/perf/benchmarks/sunspider.py b/tools/perf/benchmarks/sunspider.py
index eb212bdfe4ba766b1a9b1c6f8434e0473a9661c1..0bd1685e0d6dda4f4b691715d761fee5f759908b 100644
--- a/tools/perf/benchmarks/sunspider.py
+++ b/tools/perf/benchmarks/sunspider.py
@@ -117,11 +117,12 @@ class _SunspiderMeasurement(page_test.PageTest):
     for key, values in r.iteritems():
       results.AddValue(list_of_scalar_values.ListOfScalarValues(
           results.current_page, key, 'ms', values, important=False,
-          description=DESCRIPTIONS.get(key)))
+          description=DESCRIPTIONS.get(key), higher_is_better=False))
     results.AddValue(list_of_scalar_values.ListOfScalarValues(
         results.current_page, 'Total', 'ms', totals,
         description='Totals of run time for each different type of benchmark '
-                    'in sunspider'))
+                    'in sunspider',
+        higher_is_better=False))
 
 
 class Sunspider(benchmark.Benchmark):