Limit PassiveDocumentEventListeners to touch and make it experimental

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 49 matching lines @@
 Settings* windowSettings(LocalDOMWindow* executingWindow)
 {
     if (executingWindow) {
         if (LocalFrame* frame = executingWindow->frame()) {
             return frame->settings();
         }
     }
     return nullptr;
 }
 
+bool isTouchScrollBlockingEvent(const AtomicString& eventType)
+{
+    return eventType == EventTypeNames::touchstart
+        || eventType == EventTypeNames::touchmove;
+}
+
 bool isScrollBlockingEvent(const AtomicString& eventType)
 {
-    return eventType == EventTypeNames::touchstart
-        || eventType == EventTypeNames::touchmove
+    return isTouchScrollBlockingEvent(eventType)
         || eventType == EventTypeNames::mousewheel
         || eventType == EventTypeNames::wheel;
 }
 
 double blockedEventsWarningThreshold(const ExecutionContext* context, const Event* event)
 {
     if (!event->cancelable())
         return 0.0;
     if (!isScrollBlockingEvent(event->type()))
         return 0.0;
@@ skipping 108 matching lines @@
             options.setPassive(false);
         return;
     }
 
     if (LocalDOMWindow* executingWindow = this->executingWindow()) {
         if (options.hasPassive()) {
             UseCounter::count(executingWindow->document(), options.passive() ? UseCounter::AddEventListenerPassiveTrue : UseCounter::AddEventListenerPassiveFalse);
         }
     }
 
-    if (RuntimeEnabledFeatures::passiveDocumentEventListenersEnabled()) {
+    if (RuntimeEnabledFeatures::passiveDocumentEventListenersEnabled() && isTouchScrollBlockingEvent(eventType)) {
         if (!options.hasPassive()) {
             if (Node* node = toNode()) {
                 if (node->isDocumentNode() || node->document().documentElement() == node || node->document().body() == node) {
                     options.setPassive(true);
                     return;
                 }
             } else if (toLocalDOMWindow()) {
                 options.setPassive(true);
                 return;
             }
@@ skipping 438 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