Track input latency while starting a ServiceWorker for a navigation hint.

content/browser/renderer_host/input/render_widget_host_latency_tracker.cc

 // Copyright 2014 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 "content/browser/renderer_host/input/render_widget_host_latency_tracker.h"
 
 #include <stddef.h>
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ skipping 78 matching lines @@
 #define UMA_HISTOGRAM_SCROLL_LATENCY_SHORT(name, start, end)       \
   UMA_HISTOGRAM_CUSTOM_COUNTS(                                     \
     name,                                                          \
     (end.event_time - start.event_time).InMicroseconds(),          \
     1, 50000, 50)
 
 void ComputeScrollLatencyHistograms(
     const LatencyInfo::LatencyComponent& gpu_swap_begin_component,
     const LatencyInfo::LatencyComponent& gpu_swap_end_component,
     int64_t latency_component_id,
-    const LatencyInfo& latency) {
+    const LatencyInfo& latency,
+    bool is_running_navigation_hint_task) {
   DCHECK(!latency.coalesced());
   if (latency.coalesced())
     return;
 
   DCHECK(!gpu_swap_begin_component.event_time.is_null());
   DCHECK(!gpu_swap_end_component.event_time.is_null());
   LatencyInfo::LatencyComponent original_component;
   if (latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_FIRST_SCROLL_UPDATE_ORIGINAL_COMPONENT,
           latency_component_id, &original_component)) {
     // This UMA metric tracks the time between the final frame swap for the
     // first scroll event in a sequence and the original timestamp of that
     // scroll event's underlying touch event.
     for (size_t i = 0; i < original_component.event_count; i++) {
       UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
           "Event.Latency.TouchToFirstScrollUpdateSwapBegin",
           original_component, gpu_swap_begin_component);
     }
+    if (is_running_navigation_hint_task) {
+      for (size_t i = 0; i < original_component.event_count; i++) {
+        UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+            "Event.Latency.TouchToFirstScrollUpdateSwapBegin."

[shimazu, 2016/08/16 09:46:21]

According the top of histograms.xml, I thought "...SwapBegin_" is better here
instead of "...SwapBegin.", but the unittest works... Is there difference
between the two?

https://cs.chromium.org/chromium/src/tools/metrics/histograms/histograms.xml?...

[horo, 2016/08/16 12:31:43]

I don't know well about the regulations of what separator should be used.
But "_" is a default value.
So I should probably use "_".

I uploaded Patch Set 3.

+            "IsRunningNavigationHintTask",
+            original_component, gpu_swap_begin_component);
+      }
+    }
   } else if (!latency.FindLatency(
                  ui::INPUT_EVENT_LATENCY_SCROLL_UPDATE_ORIGINAL_COMPONENT,
                  latency_component_id, &original_component)) {
     return;
   }
 
   // This UMA metric tracks the time from when the original touch event is
   // created to when the scroll gesture results in final frame swap.
   for (size_t i = 0; i < original_component.event_count; i++) {
     UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
         "Event.Latency.TouchToScrollUpdateSwapBegin", original_component,
         gpu_swap_begin_component);
   }
+  if (is_running_navigation_hint_task) {
+    for (size_t i = 0; i < original_component.event_count; i++) {
+      UMA_HISTOGRAM_TOUCH_TO_SCROLL_LATENCY(
+          "Event.Latency.TouchToScrollUpdateSwapBegin."
+          "IsRunningNavigationHintTask",
+          original_component, gpu_swap_begin_component);
+    }
+  }
 
   // TODO(miletus): Add validation for making sure the following components
   // are present and their event times are legit.
   LatencyInfo::LatencyComponent rendering_scheduled_component;
   bool rendering_scheduled_on_main = latency.FindLatency(
       ui::INPUT_EVENT_LATENCY_RENDERING_SCHEDULED_MAIN_COMPONENT,
       0, &rendering_scheduled_component);
 
   if (!rendering_scheduled_on_main) {
     if (!latency.FindLatency(
@@ skipping 383 matching lines @@
     std::vector<LatencyInfo>* latencies) {
   DCHECK(latencies);
   for (LatencyInfo& latency : *latencies) {
     AddLatencyInfoComponentIds(&latency, latency_component_id_);
     latency.AddLatencyNumber(
         ui::INPUT_EVENT_BROWSER_RECEIVED_RENDERER_SWAP_COMPONENT, 0, 0);
   }
 }
 
 void RenderWidgetHostLatencyTracker::OnFrameSwapped(
-    const LatencyInfo& latency) {
+    const LatencyInfo& latency,
+    bool is_running_navigation_hint_task) {
   // Don't report frame latency on wheel events. Previously they were only
   // reported on touch metrics and we need to be consistent across reporting
   // metrics.
   LatencyInfo::LatencyComponent mouse_wheel_scroll_update_component;
   if (latency.FindLatency(
           ui::INPUT_EVENT_LATENCY_GENERATE_SCROLL_UPDATE_FROM_MOUSE_WHEEL, 0,
           &mouse_wheel_scroll_update_component)) {
     return;
   }
 
@@ skipping 20 matching lines @@
     }
   }
 
   if (!latency.FindLatency(ui::INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT,
                            latency_component_id_, nullptr)) {
     return;
   }
 
   ComputeScrollLatencyHistograms(gpu_swap_begin_component,
                                  gpu_swap_end_component, latency_component_id_,
-                                 latency);
+                                 latency, is_running_navigation_hint_task);
 }
 
 }  // namespace content