Add UMA/Telemetry stats for touch event latency

content/browser/renderer_host/render_widget_host_view_win.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/browser/renderer_host/render_widget_host_view_win.h"
 
 #include <dwmapi.h>
 #include <InputScope.h>
 #include <wtsapi32.h>
 #pragma comment(lib, "wtsapi32.lib")
@@ skipping 921 matching lines @@
     return;
 
   ui::EventResult result = (ack_result ==
       INPUT_EVENT_ACK_STATE_CONSUMED) ? ui::ER_HANDLED : ui::ER_UNHANDLED;
   for (ScopedVector<ui::TouchEvent>::iterator iter = events.begin(),
       end = events.end(); iter != end; ++iter)  {
     (*iter)->latency()->AddLatencyNumber(
         ui::INPUT_EVENT_LATENCY_ACKED_COMPONENT,
         static_cast<int64>(ack_result),
         0);
+    render_widget_host_->ComputeTouchLatency(*((*iter)->latency()));
     scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
     gestures.reset(gesture_recognizer_->ProcessTouchEventForGesture(
         *(*iter), result, this));
     ProcessGestures(gestures.get());
   }
 }
 
 void RenderWidgetHostViewWin::UpdateDesiredTouchMode() {
   // Make sure that touch events even make sense.
   CommandLine* cmdline = CommandLine::ForCurrentProcess();
@@ skipping 2269 matching lines @@
   return new RenderWidgetHostViewWin(widget);
 }
 
 // static
 void RenderWidgetHostViewPort::GetDefaultScreenInfo(
       WebKit::WebScreenInfo* results) {
   GetScreenInfoForWindow(0, results);
 }
 
 }  // namespace content