REGRESSION (282524@main) (iOS): Tap and click events unresponsive aft…

…er closing Safari and coming back

https://bugs.webkit.org/show_bug.cgi?id=279146
rdar://135211157

Reviewed by Abrar Rahman Protyasha.

In `PointerCaptureController`, there is logic which tries to not execute a mouse or pointer event
if there is a capturing event whose state is "Ready". However, prior to 282524@main, this logic
only worked to not execute pointer events, but would still in fact execute mouse events.

After 282524@main, since click, auxclick, and contextmenu are now pointer events, the `PointerCaptureController` logic
is now successful in preventing both mouse _and_ pointer events.

This in itself isn't a problem, and is the desired behavior when there is an active capture state.

However, in some cases (such as dismissing Safari), a touch event ends up beginning but never getting
cancelled properly. Specifically, while a `pointercancel` event is dispatched, the associated capture
data's state was never properly updated.

Fix this by calling `cancelPointer`, which properly updates the state and also more closely adheres to
the pointer event specification with regards to which events should be dispatched.

Fixing this then in turn fixes the original issue, since now there will no erroneous states which are active.

A test will be added in a follow up.

* Source/WebCore/page/PointerCaptureController.cpp:
(WebCore::PointerCaptureController::dispatchEventForTouchAtIndex):
(WebCore::PointerCaptureController::cancelPointer):
* Source/WebCore/page/PointerCaptureController.h:

Canonical link: https://commits.webkit.org/283187@main

Source/WebCore/page/PointerCaptureController.cpp

@@ -313,6 +313,13 @@ void PointerCaptureController::dispatchEventForTouchAtIndex(EventTarget& target,
         dispatchEnterOrLeaveEvent(eventNames().pointerenterEvent, *currentTarget);
     }
 
+#if PLATFORM(IOS_FAMILY)
+    if (pointerEvent->type() == eventNames().pointercancelEvent) {
+        cancelPointer(pointerEvent->pointerId(), platformTouchEvent.touchLocationAtIndex(index), pointerEvent.ptr());
+        return;
+    }
+#endif
+
     dispatchEvent(pointerEvent, &target);
 
     if (pointerEvent->type() == eventNames().pointerupEvent) {
@@ -467,7 +474,7 @@ void PointerCaptureController::pointerEventWasDispatched(const PointerEvent& eve
         capturingData->preventsCompatibilityMouseEvents = event.defaultPrevented();
 }
 
-void PointerCaptureController::cancelPointer(PointerID pointerId, const IntPoint& documentPoint)
+void PointerCaptureController::cancelPointer(PointerID pointerId, const IntPoint& documentPoint, PointerEvent* existingCancelEvent)
 {
     // https://w3c.github.io/pointerevents/#the-pointercancel-event
 
@@ -517,8 +524,14 @@ void PointerCaptureController::cancelPointer(PointerID pointerId, const IntPoint
     // followed by firing a pointer event named pointerleave.
     auto isPrimary = capturingData->isPrimary ? PointerEvent::IsPrimary::Yes : PointerEvent::IsPrimary::No;
     auto& eventNames = WebCore::eventNames();
-    auto cancelEvent = PointerEvent::create(eventNames.pointercancelEvent, pointerId, capturingData->pointerType, isPrimary);
-    target->dispatchEvent(cancelEvent);
+
+    if (existingCancelEvent)
+        target->dispatchEvent(*existingCancelEvent);
+    else {
+        auto cancelEvent = PointerEvent::create(eventNames.pointercancelEvent, pointerId, capturingData->pointerType, isPrimary);
+        target->dispatchEvent(cancelEvent);
+    }
+
     target->dispatchEvent(PointerEvent::create(eventNames.pointeroutEvent, pointerId, capturingData->pointerType, isPrimary));
     target->dispatchEvent(PointerEvent::create(eventNames.pointerleaveEvent, pointerId, capturingData->pointerType, isPrimary));
     processPendingPointerCapture(pointerId);

Source/WebCore/page/PointerCaptureController.h

@@ -67,7 +67,7 @@ class PointerCaptureController {
     bool hasCancelledPointerEventForIdentifier(PointerID) const;
     bool preventsCompatibilityMouseEventsForIdentifier(PointerID) const;
     void dispatchEvent(PointerEvent&, EventTarget*);
-    WEBCORE_EXPORT void cancelPointer(PointerID, const IntPoint&);
+    WEBCORE_EXPORT void cancelPointer(PointerID, const IntPoint&, PointerEvent* existingCancelEvent = nullptr);
     void processPendingPointerCapture(PointerID);
 
 private: