We use UMA to track event latency both as a group of all events

content/renderer/render_widget.cc

 // Copyright (c) 2012 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/renderer/render_widget.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 607 matching lines @@
       base::TimeTicks::Now().ToInternalValue());
 
   int64 delta = static_cast<int64>(
       (now.InSecondsF() - input_event->timeStampSeconds) *
           base::Time::kMicrosecondsPerSecond);
   UMA_HISTOGRAM_CUSTOM_COUNTS("Event.Latency.Renderer", delta, 0, 1000000, 100);
   std::string name_for_event =
       base::StringPrintf("Event.Latency.Renderer.%s",
                          GetEventName(input_event->type));
   base::HistogramBase* counter_for_type =
-      base::Histogram::FactoryTimeGet(
+      base::Histogram::FactoryGet(
           name_for_event,
-          base::TimeDelta::FromMilliseconds(0),
-          base::TimeDelta::FromMilliseconds(1000000),
+          0,
+          1000000,
           100,
           base::HistogramBase::kUmaTargetedHistogramFlag);
-  counter_for_type->AddTime(base::TimeDelta::FromMicroseconds(delta));
+  counter_for_type->Add(delta);
 
   bool prevent_default = false;
   if (WebInputEvent::isMouseEventType(input_event->type)) {
     const WebMouseEvent& mouse_event =
         *static_cast<const WebMouseEvent*>(input_event);
     TRACE_EVENT2("renderer", "HandleMouseMove",
                  "x", mouse_event.x, "y", mouse_event.y);
     prevent_default = WillHandleMouseEvent(mouse_event);
   }
 
@@ skipping 1492 matching lines @@
 bool RenderWidget::WillHandleGestureEvent(
     const WebKit::WebGestureEvent& event) {
   return false;
 }
 
 bool RenderWidget::HasTouchEventHandlersAt(const gfx::Point& point) const {
   return true;
 }
 
 }  // namespace content