Extract and report runs/minute for Speedometer

BUG=chromium:775410

Change-Id: I1d7596cc21435dd77d5034bcdbba1469a0c5fe0d
Reviewed-on: https://chromium-review.googlesource.com/724760Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Michael Hablich <hablich@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ben Cheng <bccheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509966}

tools/perf/benchmarks/speedometer.py

@@ -72,6 +72,12 @@ class SpeedometerMeasurement(legacy_page_test.LegacyPageTest):
         page, 'Total', 'ms',
         tab.EvaluateJavaScript('benchmarkClient._timeValues'),
         important=True))
+    results.AddValue(list_of_scalar_values.ListOfScalarValues(
+        page, 'Runs/Minute', 'score',
+        tab.EvaluateJavaScript(
+            '[parseFloat(document.getElementById("result-number").innerText)];'
+        ),
+        important=True))
 
     # Extract the timings for each suite
     for suite_name in self.enabled_suites: