Notify Blink about start of gesture scroll through a queued event.

third_party/WebKit/Source/core/input/PointerEventManager.cpp

Index: third_party/WebKit/Source/core/input/PointerEventManager.cpp
diff --git a/third_party/WebKit/Source/core/input/PointerEventManager.cpp b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
index 5a18188771175f635344fb342c9b6c0b0ac91bbf..eb7243532e7d00ed659065e93ae4e72a78d86ae2 100644
--- a/third_party/WebKit/Source/core/input/PointerEventManager.cpp
+++ b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
@@ -294,22 +294,35 @@ void PointerEventManager::setNodeUnderPointer(
     }
 }
 
-void PointerEventManager::sendTouchCancelPointerEvent(PassRefPtrWillBeRawPtr<EventTarget> prpTarget, const PlatformTouchPoint& point)
+void PointerEventManager::blockTouchPointers()
 {
-    RefPtrWillBeRawPtr<EventTarget> target = prpTarget;
-    RefPtrWillBeRawPtr<PointerEvent> pointerEvent = m_pointerEventFactory.createPointerCancelEvent(point);
+    if (m_inCanceledStateForPointerTypeTouch)
+        return;
+    m_inCanceledStateForPointerTypeTouch = true;
 
+    HeapVector<int> touchPointerIds
+        = m_pointerEventFactory.getPointerIdsOfType(WebPointerProperties::PointerType::Touch);
 
-    processCaptureAndPositionOfPointerEvent(pointerEvent, target);
+    for (int pointerId : touchPointerIds) {
+        RefPtrWillBeRawPtr<PointerEvent> pointerEvent
+            = m_pointerEventFactory.createPointerCancelEvent(
+                pointerId, WebPointerProperties::PointerType::Touch);
 
-    // TODO(nzolghadr): crbug.com/579553 dealing with implicit touch capturing vs pointer event capturing
-    dispatchPointerEvent(
-        getEffectiveTargetForPointerEvent(target, pointerEvent->pointerId()),
-        pointerEvent.get());
+        ASSERT(m_nodeUnderPointer.contains(pointerId));
+        RefPtrWillBeRawPtr<EventTarget> target = m_nodeUnderPointer.get(pointerId).target;
+
+        // TODO(crbug.com/579553): This event follows implicit TE capture. The actual target
+        // would depend on PE capturing. Perhaps need to split TE/PE event path upstream?
+        target->dispatchEvent(pointerEvent.get());
 
-    setNodeUnderPointer(pointerEvent, nullptr);
+        setNodeUnderPointer(pointerEvent, nullptr);
+        m_pointerEventFactory.remove(pointerId);
+    }
+}
 
-    removePointer(pointerEvent);
+void PointerEventManager::unblockTouchPointers()
+{
+    m_inCanceledStateForPointerTypeTouch = false;
 }
 
 WebInputEventResult PointerEventManager::sendTouchPointerEvent(
@@ -318,6 +331,9 @@ WebInputEventResult PointerEventManager::sendTouchPointerEvent(
     const double width, const double height,
     const double clientX, const double clientY)
 {
+    if (m_inCanceledStateForPointerTypeTouch)
+        return WebInputEventResult::NotHandled;
+
     RefPtrWillBeRawPtr<EventTarget> target = prpTarget;
 
     RefPtrWillBeRawPtr<PointerEvent> pointerEvent =
@@ -399,6 +415,7 @@ PointerEventManager::~PointerEventManager()
 void PointerEventManager::clear()
 {
     m_preventMouseEventForPointerTypeMouse = false;
+    m_inCanceledStateForPointerTypeTouch = false;
     m_pointerEventFactory.clear();
     m_nodeUnderPointer.clear();
 }
@@ -531,8 +548,8 @@ void PointerEventManager::removePointer(
     const PassRefPtrWillBeRawPtr<PointerEvent> prpPointerEvent)
 {
     RefPtrWillBeRawPtr<PointerEvent> pointerEvent = prpPointerEvent;
-    if (m_pointerEventFactory.remove(pointerEvent)) {
-        int pointerId = pointerEvent->pointerId();
+    int pointerId = pointerEvent->pointerId();
+    if (m_pointerEventFactory.remove(pointerId)) {
         m_pendingPointerCaptureTarget.remove(pointerId);
         m_pointerCaptureTarget.remove(pointerId);
         m_nodeUnderPointer.remove(pointerId);