Non passive touch end or touch cancel listeners should not block scroll.

third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp

Index: third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp
diff --git a/third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp b/third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp
index 5bf13bd26d69f9c1677d217ecbe2cb1c9d4f9acf..d0f0a453dd7b2919cbef70da7cc33220dba3aa23 100644
--- a/third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp
+++ b/third_party/WebKit/Source/core/frame/EventHandlerRegistry.cpp
@@ -16,14 +16,6 @@ namespace blink {
 
 namespace {
 
-inline bool isTouchEventType(const AtomicString& eventType)
-{
-    return eventType == EventTypeNames::touchstart
-        || eventType == EventTypeNames::touchmove
-        || eventType == EventTypeNames::touchend
-        || eventType == EventTypeNames::touchcancel;
-}
-
 inline bool isPointerEventType(const AtomicString& eventType)
 {
     return eventType == EventTypeNames::gotpointercapture
@@ -67,7 +59,9 @@ bool EventHandlerRegistry::eventTypeToClass(const AtomicString& eventType, const
         *result = ScrollEvent;
     } else if (eventType == EventTypeNames::wheel || eventType == EventTypeNames::mousewheel) {
         *result = options.passive() ? WheelEventPassive : WheelEventBlocking;
-    } else if (isTouchEventType(eventType)) {
+    } else if (eventType == EventTypeNames::touchend || eventType == EventTypeNames::touchcancel) {
+        *result = options.passive() ? TouchEndOrCancelEventPassive : TouchEndOrCancelEventBlocking;
+    } else if (eventType == EventTypeNames::touchstart || eventType == EventTypeNames::touchmove) {
         *result = options.passive() ? TouchEventPassive : TouchEventBlocking;
     } else if (isPointerEventType(eventType)) {
         // The EventHandlerClass is TouchEventPassive since the pointer events
@@ -213,7 +207,7 @@ void EventHandlerRegistry::notifyHasHandlersChanged(EventHandlerClass handlerCla
 {
     switch (handlerClass) {
     case ScrollEvent:
-        m_frameHost->chromeClient().setHaveScrollEventHandlers(hasActiveHandlers);
+        m_frameHost->chromeClient().setHasScrollEventHandlers(hasActiveHandlers);
         break;
     case WheelEventBlocking:
     case WheelEventPassive:
@@ -222,6 +216,12 @@ void EventHandlerRegistry::notifyHasHandlersChanged(EventHandlerClass handlerCla
     case TouchEventBlocking:
     case TouchEventPassive:
         m_frameHost->chromeClient().setEventListenerProperties(WebEventListenerClass::Touch, webEventListenerProperties(hasEventHandlers(TouchEventBlocking), hasEventHandlers(TouchEventPassive)));
+        updateHasTouchEventListeners();
+        break;
+    case TouchEndOrCancelEventBlocking:
+    case TouchEndOrCancelEventPassive:
+        m_frameHost->chromeClient().setEventListenerProperties(WebEventListenerClass::TouchEndOrCancel, webEventListenerProperties(hasEventHandlers(TouchEndOrCancelEventBlocking), hasEventHandlers(TouchEndOrCancelEventPassive)));
+        updateHasTouchEventListeners();
         break;
 #if ENABLE(ASSERT)
     case EventsForTesting:
@@ -233,6 +233,11 @@ void EventHandlerRegistry::notifyHasHandlersChanged(EventHandlerClass handlerCla
     }
 }
 
+void EventHandlerRegistry::updateHasTouchEventListeners()

[Rick Byers, 2016/04/14 01:41:40]

Why put this logic here instead of ChromeClientImpl (where it was previously)? 
Doesn't this make for more of an opportunity for things to be inconsistent? 
I.e. each caller to setEventListenerProperties for touch must remember to also
call setHasTouchEventListeners and vice versa.

[dtapuska, 2016/04/14 01:49:10]

There are only two callers to the setEventListenerProperties
1) This class
2) The FrameLoader which tries to reset the values to default values.

Ideally the FrameLoader should just call a reset method on this class.

+{
+    m_frameHost->chromeClient().setHasTouchEventListeners(hasEventHandlers(TouchEventBlocking) || hasEventHandlers(TouchEventPassive) || hasEventHandlers(TouchEndOrCancelEventBlocking) || hasEventHandlers(TouchEndOrCancelEventPassive));
+}
+
 void EventHandlerRegistry::notifyDidAddOrRemoveEventHandlerTarget(EventHandlerClass handlerClass)
 {
     ScrollingCoordinator* scrollingCoordinator = m_frameHost->page().scrollingCoordinator();