Limit PassiveDocumentEventListeners to touch and make it experimental

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 92bd274edfce15a084ab1bacf2935052978e3aef..420267bb03f72e81ae55cb96d7fb38c801ec171d 100644
--- a/third_party/WebKit/Source/core/events/EventTarget.cpp
+++ b/third_party/WebKit/Source/core/events/EventTarget.cpp
@@ -67,6 +67,12 @@ Settings* windowSettings(LocalDOMWindow* executingWindow)
     return nullptr;
 }
 
+bool isTouchScrollBlockingEvent(const AtomicString& eventType)
+{
+    return eventType == EventTypeNames::touchstart
+        || eventType == EventTypeNames::touchmove;
+}
+
 bool isScrollBlockingEvent(const AtomicString& eventType)
 {
     return eventType == EventTypeNames::touchstart

[Rick Byers, 2016/07/07 20:02:09]

nit: replace these two lines with isTouchScrollBlockingEvent just to avoid the
duplication...

[dtapuska, 2016/07/07 20:34:22]

Done.

@@ -199,7 +205,7 @@ void EventTarget::setDefaultAddEventListenerOptions(const AtomicString& eventTyp
         }
     }
 
-    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) {