Update smoothness.py to restore summarized results for metrics that don't care if some values are None:

mean_input_event_latency, input_event_latency_discrepancy, mean_scroll_update_latency, scroll_update_latency_discrepancy, first_gesture_scroll_update_latency

BUG=410018

Review URL: https://codereview.chromium.org/535783002

Cr-Commit-Position: refs/heads/master@{#293380}

2 files changed, 21 insertions, 28 deletions

diff --git a/tools/telemetry/telemetry/web_perf/metrics/smoothness.py b/tools/telemetry/telemetry/web_perf/metrics/smoothness.py
index d795194..7f10c71 100644
--- a/tools/telemetry/telemetry/web_perf/metrics/smoothness.py
+++ b/tools/telemetry/telemetry/web_perf/metrics/smoothness.py
@@ -55,15 +55,15 @@ class SmoothnessMetric(timeline_based_metric.TimelineBasedMetric):
   def _PopulateResultsFromStats(self, results, stats):
     page = results.current_page
     values = [
-        self._ComputeFirstGestureScrollUpdateLatency(page, stats),
         self._ComputeQueueingDuration(page, stats),
         self._ComputeFrameTimeDiscrepancy(page, stats),
         self._ComputeMeanPixelsApproximated(page, stats)
     ]
     values += self._ComputeLatencyMetric(page, stats, 'input_event_latency',
-                                        stats.input_event_latency)
+                                         stats.input_event_latency)
     values += self._ComputeLatencyMetric(page, stats, 'scroll_update_latency',
-                                        stats.scroll_update_latency)
+                                         stats.scroll_update_latency)
+    values += self._ComputeFirstGestureScrollUpdateLatency(page, stats)
     values += self._ComputeFrameTimeMetric(page, stats)
     for v in values:
       results.AddValue(v)
@@ -79,12 +79,11 @@ class SmoothnessMetric(timeline_based_metric.TimelineBasedMetric):
     none_value_reason = None
     if self._HasEnoughFrames(stats.frame_timestamps):
       latency_list = FlattenList(list_of_latency_lists)
-      if len(latency_list) > 0:
-        mean_latency = round(statistics.ArithmeticMean(latency_list), 3)
-        latency_discrepancy = (
-            round(statistics.DurationsDiscrepancy(latency_list), 4))
-      else:
-        none_value_reason = 'No latency values recorded.'
+      if len(latency_list) == 0:
+        return ()
+      mean_latency = round(statistics.ArithmeticMean(latency_list), 3)
+      latency_discrepancy = (
+          round(statistics.DurationsDiscrepancy(latency_list), 4))
     else:
       none_value_reason = NOT_ENOUGH_FRAMES_MESSAGE
     return (
@@ -104,20 +103,21 @@ class SmoothnessMetric(timeline_based_metric.TimelineBasedMetric):
     none_value_reason = None
     if self._HasEnoughFrames(stats.frame_timestamps):
       latency_list = FlattenList(stats.gesture_scroll_update_latency)
-      if len(latency_list) > 0:
-        first_gesture_scroll_update_latency = round(latency_list[0], 4)
-      else:
-        none_value_reason = 'No gesture scroll update latency values recorded.'
+      if len(latency_list) == 0:
+        return ()
+      first_gesture_scroll_update_latency = round(latency_list[0], 4)
     else:
       none_value_reason = NOT_ENOUGH_FRAMES_MESSAGE
-    return scalar.ScalarValue(
+    return (
+      scalar.ScalarValue(
         page, 'first_gesture_scroll_update_latency', 'ms',
         first_gesture_scroll_update_latency,
         description='First gesture scroll update latency measures the time it '
                     'takes to process the very first gesture scroll update '
                     'input event. The first scroll gesture can often get '
                     'delayed by work related to page loading.',
-        none_value_reason=none_value_reason)
+        none_value_reason=none_value_reason),
+    )
 
   def _ComputeQueueingDuration(self, page, stats):
     """Returns a Value for the frame queueing durations."""
diff --git a/tools/telemetry/telemetry/web_perf/metrics/smoothness_unittest.py b/tools/telemetry/telemetry/web_perf/metrics/smoothness_unittest.py
index aa62bdc..e21bd64 100644
--- a/tools/telemetry/telemetry/web_perf/metrics/smoothness_unittest.py
+++ b/tools/telemetry/telemetry/web_perf/metrics/smoothness_unittest.py
@@ -69,14 +69,9 @@ class SmoothnessMetricUnitTest(unittest.TestCase):
   def testComputeLatencyMetricWithMissingData(self):
     stats = _MockRenderingStats(frame_timestamps=self.good_timestamps,
                                input_event_latency=[[], []])
-    mean_value, discrepancy_value = self.metric._ComputeLatencyMetric(
+    value = self.metric._ComputeLatencyMetric(
         self.page, stats, 'input_event_latency', stats.input_event_latency)
-    self.assertEquals(None, mean_value.value)
-    self.assertEquals('No latency values recorded.',
-                      mean_value.none_value_reason)
-    self.assertEquals(None, discrepancy_value.value)
-    self.assertEquals('No latency values recorded.',
-                      discrepancy_value.none_value_reason)
+    self.assertEquals((), value)
 
   def testComputeLatencyMetricWithNotEnoughFrames(self):
     stats = _MockRenderingStats(
@@ -96,25 +91,23 @@ class SmoothnessMetricUnitTest(unittest.TestCase):
         frame_timestamps=self.good_timestamps,
         gesture_scroll_update_latency=[[10, 20], [30, 40, 50]])
     gesture_value = self.metric._ComputeFirstGestureScrollUpdateLatency(
-        self.page, stats)
+        self.page, stats)[0]
     self.assertEquals(10, gesture_value.value)
 
   def testComputeGestureScrollUpdateLatencyWithMissingData(self):
     stats = _MockRenderingStats(
         frame_timestamps=self.good_timestamps,
         gesture_scroll_update_latency=[[], []])
-    gesture_value = self.metric._ComputeFirstGestureScrollUpdateLatency(
+    value = self.metric._ComputeFirstGestureScrollUpdateLatency(
         self.page, stats)
-    self.assertEquals(None, gesture_value.value)
-    self.assertEquals('No gesture scroll update latency values recorded.',
-                      gesture_value.none_value_reason)
+    self.assertEquals((), value)
 
   def testComputeGestureScrollUpdateLatencyWithNotEnoughFrames(self):
     stats = _MockRenderingStats(
         frame_timestamps=self.not_enough_frames_timestamps,
         gesture_scroll_update_latency=[[10, 20], [30, 40, 50]])
     gesture_value = self.metric._ComputeFirstGestureScrollUpdateLatency(
-        self.page, stats)
+        self.page, stats)[0]
     self.assertEquals(None, gesture_value.value)
     self.assertEquals(smoothness.NOT_ENOUGH_FRAMES_MESSAGE,
                       gesture_value.none_value_reason)