Add getCoalescedEvents API to PointerEvent

third_party/WebKit/Source/core/events/PointerEventFactory.cpp

Index: third_party/WebKit/Source/core/events/PointerEventFactory.cpp
diff --git a/third_party/WebKit/Source/core/events/PointerEventFactory.cpp b/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
index 5c476a6c612687bb9a28480fa707b594d9a169ac..f61342f9166141bcc281d66a777cae980c843e6d 100644
--- a/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
+++ b/third_party/WebKit/Source/core/events/PointerEventFactory.cpp
@@ -75,12 +75,24 @@ unsigned short buttonToButtonsBitfield(WebPointerProperties::Button button) {
   return 0;
 }
 
-}  // namespace
-
-const int PointerEventFactory::s_invalidId = 0;
-
-// Mouse id is 1 to behave the same as MS Edge for compatibility reasons.
-const int PointerEventFactory::s_mouseId = 1;
+const AtomicString& pointerEventNameForTouchPointState(
+    PlatformTouchPoint::TouchState state) {
+  switch (state) {
+    case PlatformTouchPoint::TouchReleased:
+      return EventTypeNames::pointerup;
+    case PlatformTouchPoint::TouchCancelled:
+      return EventTypeNames::pointercancel;
+    case PlatformTouchPoint::TouchPressed:
+      return EventTypeNames::pointerdown;
+    case PlatformTouchPoint::TouchMoved:
+      return EventTypeNames::pointermove;
+    case PlatformTouchPoint::TouchStationary:
+    // Fall through to default
+    default:
+      NOTREACHED();
+      return emptyAtom;
+  }
+}
 
 float getPointerEventPressure(float force, int buttons) {
   if (std::isnan(force))
@@ -88,6 +100,67 @@ float getPointerEventPressure(float force, int buttons) {
   return force;
 }
 
+void updateTouchPointPointerEventInit(const PlatformTouchPoint& touchPoint,

[mustaq, 2016/11/21 20:53:53]

You meant "updateTouchPointerEventInit" instead?

[Navid Zolghadr, 2016/11/21 21:31:21]

Done.

+                                      LocalFrame* targetFrame,
+                                      PointerEventInit* pointerEventInit) {
+  if (targetFrame) {
+    FloatPoint pagePoint =
+        targetFrame->view()->rootFrameToContents(touchPoint.pos());
+    float scaleFactor = 1.0f / targetFrame->pageZoomFactor();
+    FloatPoint scrollPosition(targetFrame->view()->scrollOffset());
+    FloatPoint clientPoint = pagePoint.scaledBy(scaleFactor);
+    clientPoint.moveBy(scrollPosition.scaledBy(-scaleFactor));
+
+    pointerEventInit->setClientX(clientPoint.x());
+    pointerEventInit->setClientY(clientPoint.y());
+
+    FloatSize pointRadius = touchPoint.radius().scaledBy(scaleFactor);

[mustaq, 2016/11/21 20:53:53]

Radius, width & height should be outside the |if| block.

[Navid Zolghadr, 2016/11/21 21:31:21]

But scaleFactor comes from the targetFrame. What should I do in that case?

[mustaq, 2016/11/22 15:31:10]

I thought it's a bug because when target frame is null, missing client
coordinates makes sense but missing width/height doesn't. Just realized that
width/height defaults to 1 in PointerEventInit. So it looks good.

+    pointerEventInit->setWidth(pointRadius.width());
+    pointerEventInit->setHeight(pointRadius.height());
+  }
+
+  pointerEventInit->setScreenX(touchPoint.screenPos().x());
+  pointerEventInit->setScreenY(touchPoint.screenPos().y());
+  pointerEventInit->setPressure(
+      getPointerEventPressure(touchPoint.force(), pointerEventInit->buttons()));
+  pointerEventInit->setTiltX(touchPoint.pointerProperties().tiltX);
+  pointerEventInit->setTiltY(touchPoint.pointerProperties().tiltY);
+}
+
+void updateMousePointerEventInit(const PlatformMouseEvent& mouseEvent,
+                                 LocalDOMWindow* view,
+                                 PointerEventInit* pointerEventInit) {
+  pointerEventInit->setScreenX(mouseEvent.globalPosition().x());
+  pointerEventInit->setScreenY(mouseEvent.globalPosition().y());
+
+  IntPoint locationInFrameZoomed;
+  if (view && view->frame() && view->frame()->view()) {
+    LocalFrame* frame = view->frame();
+    FrameView* frameView = frame->view();
+    IntPoint locationInContents =
+        frameView->rootFrameToContents(mouseEvent.position());
+    locationInFrameZoomed = frameView->contentsToFrame(locationInContents);
+    float scaleFactor = 1 / frame->pageZoomFactor();
+    locationInFrameZoomed.scale(scaleFactor, scaleFactor);
+  }
+
+  // Set up initial values for coordinates.

[mustaq, 2016/11/21 20:53:53]

Please get rid of this old comment line, the values doesn't change as the
comment seems to suggest.

[Navid Zolghadr, 2016/11/21 21:31:21]

Done.

+  pointerEventInit->setClientX(locationInFrameZoomed.x());
+  pointerEventInit->setClientY(locationInFrameZoomed.y());
+
+  pointerEventInit->setPressure(getPointerEventPressure(
+      mouseEvent.pointerProperties().force, pointerEventInit->buttons()));
+  pointerEventInit->setTiltX(mouseEvent.pointerProperties().tiltX);
+  pointerEventInit->setTiltY(mouseEvent.pointerProperties().tiltY);
+}
+
+}  // namespace
+
+const int PointerEventFactory::s_invalidId = 0;
+
+// Mouse id is 1 to behave the same as MS Edge for compatibility reasons.
+const int PointerEventFactory::s_mouseId = 1;
+
 void PointerEventFactory::setIdTypeButtons(
     PointerEventInit& pointerEventInit,
     const WebPointerProperties& pointerProperties,
@@ -128,15 +201,20 @@ void PointerEventFactory::setEventSpecificFields(
   pointerEventInit.setDetail(0);
 }
 
-PointerEvent* PointerEventFactory::create(const AtomicString& mouseEventName,
-                                          const PlatformMouseEvent& mouseEvent,
-                                          LocalDOMWindow* view) {
+PointerEvent* PointerEventFactory::create(
+    const AtomicString& mouseEventName,
+    const PlatformMouseEvent& mouseEvent,
+    const Vector<PlatformMouseEvent>& coalescedMouseEvents,
+    LocalDOMWindow* view) {
   DCHECK(mouseEventName == EventTypeNames::mousemove ||
          mouseEventName == EventTypeNames::mousedown ||
          mouseEventName == EventTypeNames::mouseup);
 
   AtomicString pointerEventName =
       pointerEventNameForMouseEventName(mouseEventName);
+  DCHECK(pointerEventName == EventTypeNames::pointermove ||
+         coalescedMouseEvents.isEmpty());
+
   unsigned buttons =
       MouseEvent::platformModifiersToButtons(mouseEvent.getModifiers());
   PointerEventInit pointerEventInit;
@@ -144,24 +222,6 @@ PointerEvent* PointerEventFactory::create(const AtomicString& mouseEventName,
   setIdTypeButtons(pointerEventInit, mouseEvent.pointerProperties(), buttons);
   setEventSpecificFields(pointerEventInit, pointerEventName);
 
-  pointerEventInit.setScreenX(mouseEvent.globalPosition().x());
-  pointerEventInit.setScreenY(mouseEvent.globalPosition().y());
-
-  IntPoint locationInFrameZoomed;
-  if (view && view->frame() && view->frame()->view()) {
-    LocalFrame* frame = view->frame();
-    FrameView* frameView = frame->view();
-    IntPoint locationInContents =
-        frameView->rootFrameToContents(mouseEvent.position());
-    locationInFrameZoomed = frameView->contentsToFrame(locationInContents);
-    float scaleFactor = 1 / frame->pageZoomFactor();
-    locationInFrameZoomed.scale(scaleFactor, scaleFactor);
-  }
-
-  // Set up initial values for coordinates.
-  pointerEventInit.setClientX(locationInFrameZoomed.x());
-  pointerEventInit.setClientY(locationInFrameZoomed.y());
-
   if (pointerEventName == EventTypeNames::pointerdown ||
       pointerEventName == EventTypeNames::pointerup) {
     WebPointerProperties::Button button = mouseEvent.pointerProperties().button;
@@ -176,10 +236,6 @@ PointerEvent* PointerEventFactory::create(const AtomicString& mouseEventName,
     pointerEventInit.setButton(
         static_cast<int>(WebPointerProperties::Button::NoButton));
   }
-  pointerEventInit.setPressure(getPointerEventPressure(
-      mouseEvent.pointerProperties().force, pointerEventInit.buttons()));
-  pointerEventInit.setTiltX(mouseEvent.pointerProperties().tiltX);
-  pointerEventInit.setTiltY(mouseEvent.pointerProperties().tiltY);
 
   UIEventWithKeyState::setFromPlatformModifiers(pointerEventInit,
                                                 mouseEvent.getModifiers());
@@ -194,16 +250,31 @@ PointerEvent* PointerEventFactory::create(const AtomicString& mouseEventName,
 
   pointerEventInit.setView(view);
 
+  updateMousePointerEventInit(mouseEvent, view, &pointerEventInit);
+
+  // Created coalesced events init structure
+  HeapVector<Member<PointerEvent>> coalescedPointerEvents;
+  for (const auto& coalescedMouseEvent : coalescedMouseEvents) {
+    PointerEventInit coalescedEventInit = pointerEventInit;
+    updateMousePointerEventInit(coalescedMouseEvent, view, &coalescedEventInit);
+    coalescedPointerEvents.append(

[mustaq, 2016/11/21 20:53:53]

Add a DCHECK here for matching (with the container event) id, isPrimary and
pointerType.

[Navid Zolghadr, 2016/11/21 21:31:21]

I'm not sure what the DCHECK would achieve here. We don't have the container
event here yet. We only have its pointerEventInit. Beside adding that DCHECK
fills like adding a dcheck for the constructor of PointerEvent to make sure it
copies stuff from the init. Right?
Do you want me to add a DCHECK after updateMousePointerEventInit to make sure
both the modified init and the container init have the same id, isPrimary, and
pointerType?

Alternatively, I can add a DCHECK for rawId and pointerType of the given input
events o be as all the coalesced ones. However, either way even if the DCHECK
fails this function doesn't reflect the id and type of the original coalesced
events here as those will be already there in the init from the container event.

[mustaq, 2016/11/22 15:31:10]

Right but we still need to enforce the equality of these properties.
PointerEvent constructor looks like a better place, right?

[Navid Zolghadr, 2016/11/22 15:59:28]

I don't think that is the case either as that path will get called when js calls
into the constructor directly and they can set anything they want.

[mustaq, 2016/11/22 21:07:51]

Instead of the raw data checks you have added, let's check the properties in
inits (coalesced vs container) as I originally meant. We need to catch bad
values in trusted events.

This solution won't test the final event (and don't want another loop before the
|return| just for this) but we already test init->event value propagation in
other places.

Same for the touch-type create() below.

+        PointerEvent::create(pointerEventName, coalescedEventInit));
+  }
+  pointerEventInit.setCoalescedEvents(coalescedPointerEvents);
+
   return PointerEvent::create(pointerEventName, pointerEventInit);
 }
 
-PointerEvent* PointerEventFactory::create(const AtomicString& type,
-                                          const PlatformTouchPoint& touchPoint,
-                                          PlatformEvent::Modifiers modifiers,
-                                          const FloatSize& pointRadius,
-                                          const FloatPoint& clientPoint,
-                                          DOMWindow* view) {
+PointerEvent* PointerEventFactory::create(
+    const PlatformTouchPoint& touchPoint,
+    const Vector<PlatformTouchPoint>& coalescedPoints,
+    PlatformEvent::Modifiers modifiers,
+    LocalFrame* targetFrame,
+    DOMWindow* view) {
   const PlatformTouchPoint::TouchState pointState = touchPoint.state();
+  const AtomicString& type =
+      pointerEventNameForTouchPointState(touchPoint.state());
+  DCHECK(type == EventTypeNames::pointermove || coalescedPoints.isEmpty());
 
   bool pointerReleasedOrCancelled =
       pointState == PlatformTouchPoint::TouchReleased ||
@@ -216,26 +287,28 @@ PointerEvent* PointerEventFactory::create(const AtomicString& type,
 
   setIdTypeButtons(pointerEventInit, touchPoint.pointerProperties(),
                    pointerReleasedOrCancelled ? 0 : 1);
-
-  pointerEventInit.setWidth(pointRadius.width());
-  pointerEventInit.setHeight(pointRadius.height());
-  pointerEventInit.setScreenX(touchPoint.screenPos().x());
-  pointerEventInit.setScreenY(touchPoint.screenPos().y());
-  pointerEventInit.setClientX(clientPoint.x());
-  pointerEventInit.setClientY(clientPoint.y());
   pointerEventInit.setButton(static_cast<int>(
       pointerPressedOrReleased ? WebPointerProperties::Button::Left
                                : WebPointerProperties::Button::NoButton));
-  pointerEventInit.setPressure(
-      getPointerEventPressure(touchPoint.force(), pointerEventInit.buttons()));
-  pointerEventInit.setTiltX(touchPoint.pointerProperties().tiltX);
-  pointerEventInit.setTiltY(touchPoint.pointerProperties().tiltY);
+
   pointerEventInit.setView(view);
+  updateTouchPointPointerEventInit(touchPoint, targetFrame, &pointerEventInit);
 
   UIEventWithKeyState::setFromPlatformModifiers(pointerEventInit, modifiers);
 
   setEventSpecificFields(pointerEventInit, type);
 
+  // Created coalesced events init structure
+  HeapVector<Member<PointerEvent>> coalescedPointerEvents;
+  for (const auto& coalescedTouchPoint : coalescedPoints) {
+    PointerEventInit coalescedEventInit = pointerEventInit;
+    updateTouchPointPointerEventInit(coalescedTouchPoint, targetFrame,
+                                     &coalescedEventInit);
+    coalescedPointerEvents.append(

[mustaq, 2016/11/21 20:53:53]

Ditto.

+        PointerEvent::create(type, coalescedEventInit));
+  }
+  pointerEventInit.setCoalescedEvents(coalescedPointerEvents);
+
   return PointerEvent::create(type, pointerEventInit);
 }