Use WTF::TimeTicks to represent timestamp in Platform/Core event types

third_party/WebKit/Source/core/input/TouchEventManager.cpp

 // Copyright 2016 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 "core/input/TouchEventManager.h"
 
 #include "core/dom/Document.h"
 #include "core/events/TouchEvent.h"
 #include "core/frame/Deprecation.h"
 #include "core/frame/EventHandlerRegistry.h"
@@ skipping 189 matching lines @@
 
       DispatchEventResult domDispatchResult =
           touchEventTarget->dispatchEvent(touchEvent);
 
       // Only report for top level documents with a single touch on
       // touch-start or the first touch-move.
       if (event.touchStartOrFirstTouchMove() && touchInfos.size() == 1 &&
           m_frame->isMainFrame()) {
         // Record the disposition and latency of touch starts and first touch
         // moves before and after the page is fully loaded respectively.
-        int64_t latencyInMicros = static_cast<int64_t>(
-            (monotonicallyIncreasingTime() - event.timestamp()) * 1000000.0);
+        int64_t latencyInMicros =
+            (TimeTicks::Now() - event.timestamp()).InMicroseconds();
         if (event.cancelable()) {
           if (m_frame->document()->isLoadCompleted()) {
             DEFINE_STATIC_LOCAL(EnumerationHistogram,
                                 touchDispositionsAfterPageLoadHistogram,
                                 ("Event.Touch.TouchDispositionsAfterPageLoad",
                                  TouchEventDispatchResultTypeMax));
             touchDispositionsAfterPageLoadHistogram.count(
                 (domDispatchResult != DispatchEventResult::NotCanceled)
                     ? HandledTouches
                     : UnhandledTouches);
@@ skipping 285 matching lines @@
   }
 
   return dispatchTouchEvents(event, touchInfos, allTouchesReleased);
 }
 
 bool TouchEventManager::isAnyTouchActive() const {
   return m_touchPressed;
 }
 
 }  // namespace blink