Usecounter added for counting usage of addEventListener for PointerEvents.

third_party/WebKit/Source/core/events/EventTarget.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ skipping 107 matching lines @@
 
 inline LocalDOMWindow* EventTarget::executingWindow()
 {
     if (ExecutionContext* context = getExecutionContext())
         return context->executingWindow();
     return nullptr;
 }
 
 bool EventTarget::addEventListener(const AtomicString& eventType, EventListener* listener, bool useCapture)
 {
+    if (LocalDOMWindow* executingWindow = this->executingWindow()) {
+        UseCounter::count(executingWindow->document(), UseCounter::PointerEventAddListenerCount);
+    }
     EventListenerOptions options;
     setDefaultEventListenerOptionsLegacy(options, useCapture);
     return addEventListenerInternal(eventType, listener, options);
 }
 
 bool EventTarget::addEventListener(const AtomicString& eventType, EventListener* listener, const EventListenerOptionsOrBoolean& optionsUnion)
 {
     if (optionsUnion.isBoolean())
         return addEventListener(eventType, listener, optionsUnion.getAsBoolean());
     if (optionsUnion.isEventListenerOptions()) {
         EventListenerOptions options = optionsUnion.getAsEventListenerOptions();
         return addEventListener(eventType, listener, options);
     }
     return addEventListener(eventType, listener);
 }
 
 bool EventTarget::addEventListener(const AtomicString& eventType, EventListener* listener, EventListenerOptions& options)
 {
+    if (LocalDOMWindow* executingWindow = this->executingWindow()) {
+        UseCounter::count(executingWindow->document(), UseCounter::PointerEventAddListenerCount);
+    }
     setDefaultEventListenerOptions(options);
     return addEventListenerInternal(eventType, listener, options);

[mustaq, 2016/05/03 14:40:22]

- Check if it is a PointerEvent type. Otherwise, we would be counting all
"addEventListener()" uses!
- Move the counting to addEventListenerInternal(), to avoid code duplication.

[tdresser, 2016/05/03 16:13:46]

Whoooops.
Good catch...

 }
 
 bool EventTarget::addEventListenerInternal(const AtomicString& eventType, EventListener* listener, const EventListenerOptions& options)
 {
     if (!listener)
         return false;
 
     V8DOMActivityLogger* activityLogger = V8DOMActivityLogger::currentActivityLoggerIfIsolatedWorld();
     if (activityLogger) {
         Vector<String> argv;
@@ skipping 333 matching lines @@
     // they have one less listener to invoke.
     if (d->firingEventIterators) {
         for (size_t i = 0; i < d->firingEventIterators->size(); ++i) {
             d->firingEventIterators->at(i).iterator = 0;
             d->firingEventIterators->at(i).end = 0;
         }
     }
 }
 
 } // namespace blink