Add an AMP LayoutInstability BeforeInputOrScroll metric

If we decide that the non-AMP BeforeInputOrScroll variant is useful,
we'll want an AMP version to compare it to.

This change also cleans up metric descriptions in ukm.xml to no
longer refer to 'jank'.

Change-Id: Iee0f25b3ded5ce4667cd6c231acf9e7ea2b65515
Bug: 987652
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717123Reviewed-by: Steve Kobes <skobes@chromium.org>
Commit-Queue: Bryan McQuade <bmcquade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681373}

chrome/browser/page_load_metrics/observers/amp_page_load_metrics_observer.cc

@@ -192,6 +192,8 @@ void AMPPageLoadMetricsObserver::OnSubFrameRenderDataUpdate(
     return;
 
   it->second.render_data.layout_shift_score += render_data.layout_shift_delta;
+  it->second.render_data.layout_shift_score_before_input_or_scroll +=
+      render_data.layout_shift_delta_before_input_or_scroll;
 }
 
 void AMPPageLoadMetricsObserver::OnComplete(
@@ -420,10 +422,17 @@ void AMPPageLoadMetricsObserver::MaybeRecordAmpDocumentMetrics() {
   // full-frame layout shifts.
   float clamped_shift_score =
       std::min(subframe_info.render_data.layout_shift_score, 10.0f);
+  float clamped_shift_score_before_input_or_scroll = std::min(
+      subframe_info.render_data.layout_shift_score_before_input_or_scroll,
+      10.0f);
 
   // For UKM, report (shift_score * 100) as an int in the range [0, 1000].
-  builder.SetSubFrame_LayoutInstability_CumulativeShiftScore(
-      static_cast<int>(roundf(clamped_shift_score * 100.0f)));
+  builder
+      .SetSubFrame_LayoutInstability_CumulativeShiftScore(
+          static_cast<int>(roundf(clamped_shift_score * 100.0f)))
+      .SetSubFrame_LayoutInstability_CumulativeShiftScore_BeforeInputOrScroll(
+          static_cast<int>(
+              roundf(clamped_shift_score_before_input_or_scroll * 100.0f)));
 
   // For UMA, report (shift_score * 10) an an int in the range [0,100].
   int32_t uma_value = static_cast<int>(roundf(clamped_shift_score * 10.0f));

chrome/browser/page_load_metrics/observers/amp_page_load_metrics_observer_unittest.cc

@@ -373,7 +373,7 @@ TEST_F(AMPPageLoadMetricsObserverTest, SubFrameMetrics_LayoutInstability) {
       blink::WebLoadingBehaviorFlag::kWebLoadingBehaviorAmpDocumentLoaded;
   SimulateMetadataUpdate(metadata, subframe);
 
-  page_load_metrics::mojom::FrameRenderDataUpdate render_data(1.0, 1.0);
+  page_load_metrics::mojom::FrameRenderDataUpdate render_data(1.0, 0.5);
   SimulateRenderDataUpdate(render_data, subframe);
 
   // Navigate the main frame to trigger metrics recording.
@@ -390,6 +390,10 @@ TEST_F(AMPPageLoadMetricsObserverTest, SubFrameMetrics_LayoutInstability) {
   test_ukm_recorder().ExpectEntrySourceHasUrl(entry.get(), amp_url);
   test_ukm_recorder().ExpectEntryMetric(
       entry.get(), "SubFrame.LayoutInstability.CumulativeShiftScore", 100);
+  test_ukm_recorder().ExpectEntryMetric(
+      entry.get(),
+      "SubFrame.LayoutInstability.CumulativeShiftScore.BeforeInputOrScroll",
+      50);
 }
 
 TEST_F(AMPPageLoadMetricsObserverTest, SubFrameMetricsFullNavigation) {

tools/metrics/ukm/ukm.xml

@@ -296,9 +296,19 @@ be describing additional metrics about the same event.
   </metric>
   <metric name="SubFrame.LayoutInstability.CumulativeShiftScore">
     <summary>
-      Measures the amount of layout jank (bit.ly/lsm-explainer) that has
+      Measures the cumulative layout shift (bit.ly/lsm-explainer) that has
       occurred during the session, in the AMP subframe. This metric's integral
-      value is 100x the fractional jank score described in the explainer.
+      value is 100x the fractional cumulative layout shift score described in
+      the explainer.
+    </summary>
+  </metric>
+  <metric
+      name="SubFrame.LayoutInstability.CumulativeShiftScore.BeforeInputOrScroll">
+    <summary>
+      Measures the cumulative layout shift (bit.ly/lsm-explainer) that has
+      occurred in the AMP subframe, before any user input or document scroll.
+      This metric's integral value is 100x the fractional cumulative layout
+      shift score described in the explainer.
     </summary>
   </metric>
   <metric name="SubFrame.LayoutStability.JankScore">
@@ -5377,26 +5387,27 @@ be describing additional metrics about the same event.
   </metric>
   <metric name="LayoutInstability.CumulativeShiftScore">
     <summary>
-      Measures the amount of layout jank (bit.ly/lsm-explainer) that has
+      Measures the cumulative layout shift (bit.ly/lsm-explainer) that has
       occurred on the page (including all subframes) during the session. This
-      metric's integral value is 100x the fractional jank score described in the
-      explainer.
+      metric's integral value is 100x the fractional cumulative layout shift
+      score described in the explainer.
     </summary>
   </metric>
   <metric name="LayoutInstability.CumulativeShiftScore.MainFrame">
     <summary>
-      Measures the amount of layout jank (bit.ly/lsm-explainer) that has
+      Measures the cumulative layout shift (bit.ly/lsm-explainer) that has
       occurred in the main frame during the session. This metric's integral
-      value is 100x the fractional jank score described in the explainer.
+      value is 100x the fractional cumulative layout shift score described in
+      the explainer.
     </summary>
   </metric>
   <metric
       name="LayoutInstability.CumulativeShiftScore.MainFrame.BeforeInputOrScroll">
     <summary>
-      Measures the amount of layout jank (bit.ly/lsm-explainer) that has
+      Measures the cumulative layout shift (bit.ly/lsm-explainer) that has
       occurred in the main frame during the session, before any user input or
-      document scroll. This metric's integral value is 100x the fractional jank
-      score described in the explainer.
+      document scroll. This metric's integral value is 100x the fractional
+      cumulative layout shift score described in the explainer.
     </summary>
   </metric>
   <metric name="LayoutStability.JankScore">