Usecounter added for counting usage of addEventListener for PointerEvents.

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

Index: third_party/WebKit/Source/core/events/EventTarget.cpp
diff --git a/third_party/WebKit/Source/core/events/EventTarget.cpp b/third_party/WebKit/Source/core/events/EventTarget.cpp
index 230c6756ff1dd0844ccd0969d4815389b1012a73..df4d1a1798428cced1da7ca7502ab37cb9f622b5 100644
--- a/third_party/WebKit/Source/core/events/EventTarget.cpp
+++ b/third_party/WebKit/Source/core/events/EventTarget.cpp
@@ -125,6 +125,9 @@ inline LocalDOMWindow* EventTarget::executingWindow()
 
 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);
@@ -143,6 +146,9 @@ bool EventTarget::addEventListener(const AtomicString& eventType, EventListener*
 
 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...

 }