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

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/input/PointerEventManager.h"
 
 #include "core/dom/shadow/FlatTreeTraversal.h"
 #include "core/events/MouseEvent.h"
 #include "core/input/EventHandler.h"
 
@@ skipping 265 matching lines @@
         if (sendEvent)
             sendNodeTransitionEvents(node.target, target, pointerEvent);
     } else if (target) {
         m_nodeUnderPointer.add(pointerEvent->pointerId(),
             EventTargetAttributes(target, false));
         if (sendEvent)
             sendNodeTransitionEvents(nullptr, target, pointerEvent);
     }
 }
 
-void PointerEventManager::sendTouchCancelPointerEvent(EventTarget* target, const PlatformTouchPoint& point)
+void PointerEventManager::blockTouchPointers()
 {
-    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) {
+        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);
+        ASSERT(m_nodeUnderPointer.contains(pointerId));
+        EventTarget* target = m_nodeUnderPointer.get(pointerId).target;
 
-    releasePointerCapture(pointerEvent->pointerId());
+        processCaptureAndPositionOfPointerEvent(pointerEvent, target);
 
-    // Sending the leave/out events and lostpointercapture
-    // because the next touch event will have a different id. So delayed
-    // sending of lostpointercapture won't work here.
-    processCaptureAndPositionOfPointerEvent(pointerEvent, nullptr);
+        // TODO(crbug.com/579553): This event follows implicit TE capture. The actual target

[bokan, 2016/04/11 22:22:00]

Please keep the TODO format from before: |TODO(name): Description|.

[mustaq, 2016/04/12 17:16:14]

My interpretation of the Blink style guide entry
(https://www.chromium.org/blink/coding-style) is that our cpp style
(https://google.github.io/styleguide/cppguide.html#TODO_Comments) overrides it.
This is because the Blink style points to the general cpp style, and the recent
FIXME-to-TODO change in documentation seems to be a search/replace w/o much
thought. Agree/disagree?

+        // would depend on PE capturing. Perhaps need to split TE/PE event path upstream?
+        dispatchPointerEvent(
+            getEffectiveTargetForPointerEvent(target, pointerEvent->pointerId()),
+            pointerEvent);
 
-    removePointer(pointerEvent);
+        releasePointerCapture(pointerEvent->pointerId());
+
+        // Sending the leave/out events and lostpointercapture
+        // because the next touch event will have a different id. So delayed
+        // sending of lostpointercapture won't work here.
+        processCaptureAndPositionOfPointerEvent(pointerEvent, nullptr);
+
+        removePointer(pointerEvent);
+    }
+}
+
+void PointerEventManager::unblockTouchPointers()
+{
+    m_inCanceledStateForPointerTypeTouch = false;
 }
 
 WebInputEventResult PointerEventManager::sendTouchPointerEvent(
     EventTarget* target,
     const PlatformTouchPoint& touchPoint, PlatformEvent::Modifiers modifiers,
     const double width, const double height,
     const double clientX, const double clientY)
 {
+    if (m_inCanceledStateForPointerTypeTouch)
+        return WebInputEventResult::NotHandled;
+
     PointerEvent* pointerEvent =
         m_pointerEventFactory.create(
         pointerEventNameForTouchPointState(touchPoint.state()),
         touchPoint, modifiers, width, height, clientX, clientY);
 
     processCaptureAndPositionOfPointerEvent(pointerEvent, target);
 
     // TODO(nzolghadr): crbug.com/579553 dealing with implicit touch capturing vs pointer event capturing
     WebInputEventResult result = dispatchPointerEvent(
         getEffectiveTargetForPointerEvent(target, pointerEvent->pointerId()),
@@ skipping 67 matching lines @@
     clear();
 }
 
 PointerEventManager::~PointerEventManager()
 {
 }
 
 void PointerEventManager::clear()
 {
     m_preventMouseEventForPointerTypeMouse = false;
+    m_inCanceledStateForPointerTypeTouch = false;
     m_pointerEventFactory.clear();
     m_nodeUnderPointer.clear();
     m_pointerCaptureTarget.clear();
     m_pendingPointerCaptureTarget.clear();
 }
 
 void PointerEventManager::processCaptureAndPositionOfPointerEvent(
     PointerEvent* pointerEvent,
     EventTarget* hitTestTarget,
     EventTarget* lastNodeUnderMouse,
@@ skipping 109 matching lines @@
 EventTarget* PointerEventManager::getCapturingNode(int pointerId)
 {
     if (m_pointerCaptureTarget.contains(pointerId))
         return m_pointerCaptureTarget.get(pointerId);
     return nullptr;
 }
 
 void PointerEventManager::removePointer(
     PointerEvent* pointerEvent)
 {
-    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);
     }
 }
 
 void PointerEventManager::elementRemoved(EventTarget* target)
 {
     removeTargetFromPointerCapturingMapping(m_pendingPointerCaptureTarget, target);
 }
@@ skipping 28 matching lines @@
 
 DEFINE_TRACE(PointerEventManager)
 {
     visitor->trace(m_nodeUnderPointer);
     visitor->trace(m_pointerCaptureTarget);
     visitor->trace(m_pendingPointerCaptureTarget);
 }
 
 
 } // namespace blink