Added UseCounters for touchstart, mousedown, pointerdown invocation

third_party/WebKit/Source/core/input/PointerEventManager.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/PointerEventManager.h"
 
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/shadow/FlatTreeTraversal.h"
 #include "core/events/MouseEvent.h"
 #include "core/frame/FrameView.h"
@@ skipping 138 matching lines @@
             m_nodeUnderPointer.set(pointerId, EventTargetAttributes
                 (targetUnderPointer,
                 eventType == EventTypeNames::pointerover));
         }
     }
 
     if (!RuntimeEnabledFeatures::pointerEventEnabled())
         return WebInputEventResult::NotHandled;
     if (!checkForListener || target->hasEventListeners(eventType)) {
         UseCounter::count(m_frame->document(), UseCounter::PointerEventDispatch);
+        if (eventType == EventTypeNames::pointerdown)
+            UseCounter::count(m_frame->document(), UseCounter::PointerEventDispatchPointerDown);
+
         DispatchEventResult dispatchResult = target->dispatchEvent(pointerEvent);
         return EventHandler::toWebInputEventResult(dispatchResult);
     }
     return WebInputEventResult::NotHandled;
 }
 
 EventTarget* PointerEventManager::getEffectiveTargetForPointerEvent(
     EventTarget* target, int pointerId)
 {
     if (EventTarget* capturingTarget = getCapturingNode(pointerId))
@@ skipping 634 matching lines @@
 {
     visitor->trace(m_frame);
     visitor->trace(m_nodeUnderPointer);
     visitor->trace(m_pointerCaptureTarget);
     visitor->trace(m_pendingPointerCaptureTarget);
     visitor->trace(m_touchEventManager);
 }
 
 
 } // namespace blink