Add UMA metric for tracking root level listeners for blocking touch.

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 466 matching lines @@
     if (!d)
         return DispatchEventResult::NotCanceled;
 
     EventListenerVector* legacyListenersVector = nullptr;
     AtomicString legacyTypeName = legacyType(event);
     if (!legacyTypeName.isEmpty())
         legacyListenersVector = d->eventListenerMap.find(legacyTypeName);
 
     EventListenerVector* listenersVector = d->eventListenerMap.find(event->type());
 
+    bool firedEventListeners = false;
     if (listenersVector) {
-        fireEventListeners(event, d, *listenersVector);
+        firedEventListeners = fireEventListeners(event, d, *listenersVector);
     } else if (legacyListenersVector) {
         AtomicString unprefixedTypeName = event->type();
         event->setType(legacyTypeName);
-        fireEventListeners(event, d, *legacyListenersVector);
+        firedEventListeners = fireEventListeners(event, d, *legacyListenersVector);
         event->setType(unprefixedTypeName);
     }
 
+    // Only invoke the callback if event listeners were fired for this phase.
+    if (firedEventListeners)
+        event->doneDispatchingEventAtCurrentTarget();
+
+    // TODO(dtapuska: Should we really do counting here for these events
+    // if we really didn't fire a listener? For example having a bubbling
+    // listener on an event that doesn't bubble likely records a UMA
+    // metric where it probably shouldn't because it was never fired.

[tdresser, 2016/05/18 13:23:10]

Can you file and link a bug for this?

[dtapuska, 2016/05/18 15:24:04]

Done.

     Editor::countEvent(getExecutionContext(), event);
     countLegacyEvents(legacyTypeName, listenersVector, legacyListenersVector);
     return dispatchEventResult(*event);
 }
 
-void EventTarget::fireEventListeners(Event* event, EventTargetData* d, EventListenerVector& entry)
+bool EventTarget::fireEventListeners(Event* event, EventTargetData* d, EventListenerVector& entry)
 {
     // Fire all listeners registered for this event. Don't fire listeners removed
     // during event dispatch. Also, don't fire event listeners added during event
     // dispatch. Conveniently, all new event listeners will be added after or at
     // index |size|, so iterating up to (but not including) |size| naturally excludes
     // new event listeners.
 
     if (event->type() == EventTypeNames::beforeunload) {
         if (LocalDOMWindow* executingWindow = this->executingWindow()) {
             if (executingWindow->top())
                 UseCounter::count(executingWindow->document(), UseCounter::SubFrameBeforeUnloadFired);
             UseCounter::count(executingWindow->document(), UseCounter::DocumentBeforeUnloadFired);
         }
     } else if (event->type() == EventTypeNames::unload) {
         if (LocalDOMWindow* executingWindow = this->executingWindow())
             UseCounter::count(executingWindow->document(), UseCounter::DocumentUnloadFired);
     } else if (event->type() == EventTypeNames::DOMFocusIn || event->type() == EventTypeNames::DOMFocusOut) {
         if (LocalDOMWindow* executingWindow = this->executingWindow())
             UseCounter::count(executingWindow->document(), UseCounter::DOMFocusInOutEvent);
     } else if (event->type() == EventTypeNames::focusin || event->type() == EventTypeNames::focusout) {
         if (LocalDOMWindow* executingWindow = this->executingWindow())
             UseCounter::count(executingWindow->document(), UseCounter::FocusInOutEvent);
     } else if (event->type() == EventTypeNames::textInput) {
         if (LocalDOMWindow* executingWindow = this->executingWindow())
             UseCounter::count(executingWindow->document(), UseCounter::TextInputFired);
     }
 
     ExecutionContext* context = getExecutionContext();
     if (!context)
-        return;
+        return false;
 
     size_t i = 0;
     size_t size = entry.size();
     if (!d->firingEventIterators)
         d->firingEventIterators = adoptPtr(new FiringEventIteratorVector);
     d->firingEventIterators->append(FiringEventIterator(event->type(), i, size));
 
     double blockedEventThreshold = blockedEventsWarningThreshold(context, event);
     double now = 0.0;
     bool shouldReportBlockedEvent = false;
     if (blockedEventThreshold) {
         now = WTF::monotonicallyIncreasingTime();
         shouldReportBlockedEvent = now - event->platformTimeStamp() > blockedEventThreshold;
     }
+    bool firedListener = false;
 
     while (i < size) {
         RegisteredEventListener& registeredListener = entry[i];
 
         // Move the iterator past this event listener. This must match
         // the handling of the FiringEventIterator::iterator in
         // EventTarget::removeEventListener.
         ++i;
 
         if (event->eventPhase() == Event::CAPTURING_PHASE && !registeredListener.capture())
             continue;
         if (event->eventPhase() == Event::BUBBLING_PHASE && registeredListener.capture())
             continue;
 
         // If stopImmediatePropagation has been called, we just break out immediately, without
         // handling any more events on this target.
         if (event->immediatePropagationStopped())
             break;
 
         event->setHandlingPassive(registeredListener.passive());
 
         InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(context, this, event);
 
         // To match Mozilla, the AT_TARGET phase fires both capturing and bubbling
         // event listeners, even though that violates some versions of the DOM spec.
         registeredListener.listener()->handleEvent(context, event);
+        firedListener = true;
 
         if (shouldReportBlockedEvent && !registeredListener.passive() && !registeredListener.blockedEventWarningEmitted() && !event->defaultPrevented())
             reportBlockedEvent(context, event, &registeredListener, now - event->platformTimeStamp());
 
         event->setHandlingPassive(false);
 
         RELEASE_ASSERT(i <= size);
     }
     d->firingEventIterators->removeLast();
+    return firedListener;
 }
 
 DispatchEventResult EventTarget::dispatchEventResult(const Event& event)
 {
     if (event.defaultPrevented())
         return DispatchEventResult::CanceledByEventHandler;
     if (event.defaultHandled())
         return DispatchEventResult::CanceledByDefaultEventHandler;
     return DispatchEventResult::NotCanceled;
 }
@@ skipping 23 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