Update service_worker to use results.AddValue(...)

tools/perf/benchmarks/service_worker.py

Index: tools/perf/benchmarks/service_worker.py
diff --git a/tools/perf/benchmarks/service_worker.py b/tools/perf/benchmarks/service_worker.py
index 891dad26abebe13fbab59db67b7b0c94a2077ba8..7f72753605ba79630305b90ef24e1b492333b2b9 100644
--- a/tools/perf/benchmarks/service_worker.py
+++ b/tools/perf/benchmarks/service_worker.py
@@ -5,6 +5,7 @@
 import page_sets
 from telemetry import benchmark
 from telemetry.page import page_measurement
+from telemetry.value import scalar
 
 
 class _ServiceWorkerMeasurement(page_measurement.PageMeasurement):
@@ -17,7 +18,8 @@ class _ServiceWorkerMeasurement(page_measurement.PageMeasurement):
     tab.WaitForJavaScriptExpression('window.done', 40)
     json = tab.EvaluateJavaScript('window.results')
     for key, value in json.iteritems():
-      results.Add(key, value['units'], value['value'])
+      results.AddValue(scalar.ScalarValue(
+          results.current_page, key, value['units'], value['value']))
 
 
 @benchmark.Disabled