Collect metrics in HitTestAggregator and HitTestQuery.

Collect Event.VizHitTest.AggregateTime, Event.VizHitTest.HitTestRegions,
Event.VizHitTest.TargetTime and Event.VizHitTest.TransformTime.

Bug: 817673
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: Iaae1009aa74f679a2e40c56f62e24a6fb3422be4
Reviewed-on: https://chromium-review.googlesource.com/942604
Commit-Queue: Ria Jiang <riajiang@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540270}

components/viz/host/hit_test/hit_test_query.cc

@@ -4,6 +4,7 @@
 
 #include "components/viz/host/hit_test/hit_test_query.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "services/viz/public/interfaces/hit_test/hit_test_region_list.mojom.h"
 #include "ui/gfx/geometry/point_conversions.h"
 
@@ -53,6 +54,8 @@ void HitTestQuery::SwitchActiveAggregatedHitTestRegionList(
 Target HitTestQuery::FindTargetForLocation(
     EventSource event_source,
     const gfx::PointF& location_in_root) const {
+  SCOPED_UMA_HISTOGRAM_TIMER("Event.VizHitTest.TargetTime");
+
   Target target;
   if (!active_hit_test_list_size_)
     return target;
@@ -66,6 +69,8 @@ gfx::PointF HitTestQuery::TransformLocationForTarget(
     EventSource event_source,
     const std::vector<FrameSinkId>& target_ancestors,
     const gfx::PointF& location_in_root) const {
+  SCOPED_UMA_HISTOGRAM_TIMER("Event.VizHitTest.TransformTime");
+
   if (!active_hit_test_list_size_)
     return location_in_root;
 

components/viz/service/hit_test/hit_test_aggregator.cc

@@ -4,6 +4,7 @@
 
 #include "components/viz/service/hit_test/hit_test_aggregator.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "components/viz/common/hit_test/aggregated_hit_test_region.h"
 #include "components/viz/service/hit_test/hit_test_aggregator_delegate.h"
 #include "third_party/skia/include/core/SkMatrix44.h"
@@ -103,6 +104,8 @@ void HitTestAggregator::SwapHandles() {
 }
 
 void HitTestAggregator::AppendRoot(const SurfaceId& surface_id) {
+  SCOPED_UMA_HISTOGRAM_TIMER("Event.VizHitTest.AggregateTime");
+
   const mojom::HitTestRegionList* hit_test_region_list =
       hit_test_manager_->GetActiveHitTestRegionList(surface_id);
   if (!hit_test_region_list)
@@ -117,6 +120,7 @@ void HitTestAggregator::AppendRoot(const SurfaceId& surface_id) {
 
   DCHECK_GE(region_index, 1u);
   int32_t child_count = region_index - 1;
+  UMA_HISTOGRAM_COUNTS_1000("Event.VizHitTest.HitTestRegions", region_index);
   SetRegionAt(0, surface_id.frame_sink_id(), hit_test_region_list->flags,
               hit_test_region_list->bounds, hit_test_region_list->transform,
               child_count);

tools/metrics/histograms/histograms.xml

@@ -22563,6 +22563,41 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Event.VizHitTest.AggregateTime" units="ms">
+  <owner>riajiang@chromium.org</owner>
+  <owner>event-targeting@chromium.org</owner>
+  <summary>
+    Tracks how long it takes for HitTestAggregator to aggregate hit-test data
+    received from all clients.
+  </summary>
+</histogram>
+
+<histogram name="Event.VizHitTest.HitTestRegions" units="regions">
+  <owner>riajiang@chromium.org</owner>
+  <owner>event-targeting@chromium.org</owner>
+  <summary>
+    Total number of hit-test regions Viz received from all clients.
+  </summary>
+</histogram>
+
+<histogram name="Event.VizHitTest.TargetTime" units="ms">
+  <owner>riajiang@chromium.org</owner>
+  <owner>event-targeting@chromium.org</owner>
+  <summary>
+    Tracks how long it takes for HitTestQuery to find a target on a given
+    location.
+  </summary>
+</histogram>
+
+<histogram name="Event.VizHitTest.TransformTime" units="ms">
+  <owner>riajiang@chromium.org</owner>
+  <owner>event-targeting@chromium.org</owner>
+  <summary>
+    Tracks how long it takes for HitTestQuery to transform a location to a given
+    target's coordinate space.
+  </summary>
+</histogram>
+
 <histogram name="ExclusiveAccess.BubbleReshowsPerSession.Fullscreen">
   <owner>mgiuca@chromium.org</owner>
   <summary>