Add TimeToScrollUpdateSwapBegin2 to UKM

ui/latency/latency_tracker.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/latency/latency_tracker.h"
 
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "ui/latency/latency_histogram_macros.h"
 
@@ skipping 102 matching lines @@
 }
 
 void LatencyTracker::ReportRapporScrollLatency(
     const std::string& name,
     const LatencyInfo::LatencyComponent& start_component,
     const LatencyInfo::LatencyComponent& end_component) {
   // TODO(mfomitchev): crbug.com/717629: Make RAPPOR or UKM reporting work with
   // Mus.
 }
 
+void LatencyTracker::ReportUkmScrollLatency(
+    const std::string& name,
+    const LatencyInfo::LatencyComponent& start_component,
+    const LatencyInfo::LatencyComponent& end_component) {
+  // TODO(mfomitchev): crbug.com/717629: Make RAPPOR or UKM reporting work with
+  // Mus.
+}
+
 void LatencyTracker::ComputeEndToEndLatencyHistograms(
     const ui::LatencyInfo::LatencyComponent& gpu_swap_begin_component,
     const ui::LatencyInfo::LatencyComponent& gpu_swap_end_component,
     const ui::LatencyInfo& latency) {
   DCHECK(!latency.coalesced());
   if (latency.coalesced())
     return;
 
   LatencyInfo::LatencyComponent original_component;
   std::string scroll_name = "ScrollUpdate";
@@ skipping 30 matching lines @@
     // created to when the scroll gesture results in final frame swap.
     // First scroll events are excluded from this metric.
     if (input_modality == "Touch") {
       UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
           "Event.Latency.ScrollUpdate.Touch.TimeToScrollUpdateSwapBegin2",
           original_component, gpu_swap_begin_component);
 
       ReportRapporScrollLatency(
           "Event.Latency.ScrollUpdate.Touch.TimeToScrollUpdateSwapBegin2",
           original_component, gpu_swap_begin_component);
+      ReportUkmScrollLatency(
+          "Event.Latency.ScrollUpdate.Touch.TimeToScrollUpdateSwapBegin2",
+          original_component, gpu_swap_begin_component);
     }
   } else if (latency.FindLatency(ui::INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, 0,
                                  &original_component)) {
     if (input_modality == "KeyPress") {
       UMA_HISTOGRAM_INPUT_LATENCY_HIGH_RESOLUTION_MICROSECONDS(
           "Event.Latency.EndToEnd.KeyPress", original_component,
           gpu_swap_begin_component);
     }
   } else {
     // No original component found.
@@ skipping 42 matching lines @@
       "Event.Latency." + scroll_name + "." + input_modality +
           ".BrowserNotifiedToBeforeGpuSwap2",
       browser_received_swap_component, gpu_swap_begin_component);
 
   UMA_HISTOGRAM_SCROLL_LATENCY_SHORT_2(
       "Event.Latency." + scroll_name + "." + input_modality + ".GpuSwap2",
       gpu_swap_begin_component, gpu_swap_end_component);
 }
 
 }  // namespace ui