Extract touch handling logic from EventHandler

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

Index: third_party/WebKit/Source/core/input/EventHandler.cpp
diff --git a/third_party/WebKit/Source/core/input/EventHandler.cpp b/third_party/WebKit/Source/core/input/EventHandler.cpp
index 3e20b960f3321477f0ddd74a9d3aaa41e26d9055..7a9a4b630908f4cab20d4c8c4b32f49406b2e60a 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandler.cpp
@@ -58,7 +58,6 @@
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/frame/VisualViewport.h"
-#include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/html/HTMLFrameSetElement.h"
@@ -107,31 +106,6 @@ namespace blink {
 
 namespace {
 
-bool hasTouchHandlers(const EventHandlerRegistry& registry)
-{
-    return registry.hasEventHandlers(EventHandlerRegistry::TouchEventBlocking)
-        || registry.hasEventHandlers(EventHandlerRegistry::TouchEventPassive);
-}
-
-const AtomicString& touchEventNameForTouchPointState(PlatformTouchPoint::TouchState state)
-{
-    switch (state) {
-    case PlatformTouchPoint::TouchReleased:
-        return EventTypeNames::touchend;
-    case PlatformTouchPoint::TouchCancelled:
-        return EventTypeNames::touchcancel;
-    case PlatformTouchPoint::TouchPressed:
-        return EventTypeNames::touchstart;
-    case PlatformTouchPoint::TouchMoved:
-        return EventTypeNames::touchmove;
-    case PlatformTouchPoint::TouchStationary:
-        // Fall through to default
-    default:
-        ASSERT_NOT_REACHED();
-        return emptyAtom;
-    }
-}
-
 // Convert |event->deltaMode()| to scroll granularity and output as |granularity|.
 bool wheelGranularityToScrollGranularity(const WheelEvent* event, ScrollGranularity* granularity)
 {
@@ -269,7 +243,7 @@ EventHandler::EventHandler(LocalFrame* frame)
     , m_accumulatedRootOverscroll(FloatSize())
     , m_mousePositionIsUnknown(true)
     , m_mouseDownTimestamp(0)
-    , m_touchPressed(false)
+    , m_pointerEventManager(frame)
     , m_scrollGestureHandlingNode(nullptr)
     , m_lastGestureScrollOverWidget(false)
     , m_longTapShouldInvokeContextMenu(false)
@@ -297,9 +271,6 @@ DEFINE_TRACE(EventHandler)
     visitor->trace(m_dragTarget);
     visitor->trace(m_frameSetBeingResized);
     visitor->trace(m_scrollbarHandlingScrollGesture);
-    visitor->trace(m_targetForTouchID);
-    visitor->trace(m_regionForTouchID);
-    visitor->trace(m_touchSequenceDocument);
     visitor->trace(m_scrollGestureHandlingNode);
     visitor->trace(m_previousGestureScrolledNode);
     visitor->trace(m_lastDeferredTapElement);
@@ -336,13 +307,9 @@ void EventHandler::clear()
     m_mousePressed = false;
     m_capturesDragging = false;
     m_capturingMouseEventsNode = nullptr;
-    m_targetForTouchID.clear();
-    m_touchSequenceDocument.clear();
-    m_touchSequenceUserGestureToken.clear();
     clearGestureScrollState();
     m_lastGestureScrollOverWidget = false;
     m_scrollbarHandlingScrollGesture = nullptr;
-    m_touchPressed = false;
     m_pointerEventManager.clear();
     m_mouseDownMayStartDrag = false;
     m_lastShowPressTimestamp = 0;
@@ -1222,7 +1189,7 @@ WebInputEventResult EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMous
     }
 
     // Treat any mouse move events as readonly if the user is currently touching the screen.
-    if (m_touchPressed)
+    if (m_pointerEventManager.getTouchEventManager().isAnyTouchActive())
         hitType |= HitTestRequest::Active | HitTestRequest::ReadOnly;
     HitTestRequest request(hitType);
     MouseEventWithHitTestResults mev = MouseEventWithHitTestResults(mouseEvent, HitTestResult(request, LayoutPoint()));
@@ -3572,359 +3539,11 @@ HitTestResult EventHandler::hitTestResultInFrame(LocalFrame* frame, const Layout
     return result;
 }
 
-void EventHandler::dispatchPointerEvents(const PlatformTouchEvent& event,
-    HeapVector<TouchInfo>& touchInfos)
-{
-    if (!RuntimeEnabledFeatures::pointerEventEnabled())
-        return;
-
-    // Iterate through the touch points, sending PointerEvents to the targets as required.
-    for (unsigned i = 0; i < touchInfos.size(); ++i) {
-        TouchInfo& touchInfo = touchInfos[i];
-        const PlatformTouchPoint& touchPoint = touchInfo.point;
-
-
-        if (touchPoint.state() == PlatformTouchPoint::TouchStationary
-            || !touchInfo.knownTarget)
-            continue;
-
-        WebInputEventResult result =
-            m_pointerEventManager.sendTouchPointerEvent(
-            touchInfo.touchTarget, touchPoint, event.getModifiers(),
-            touchInfo.adjustedRadius.width(), touchInfo.adjustedRadius.height(),
-            touchInfo.adjustedPagePoint.x(), touchInfo.adjustedPagePoint.y());
-        touchInfo.consumed = result != WebInputEventResult::NotHandled;
-    }
-}
-
-namespace {
-
-// Defining this class type local to dispatchTouchEvents() and annotating
-// it with STACK_ALLOCATED(), runs into MSVC(VS 2013)'s C4822 warning
-// that the local class doesn't provide a local definition for 'operator new'.
-// Which it intentionally doesn't and shouldn't.
-//
-// Work around such toolchain bugginess by lifting out the type, thereby
-// taking it out of C4822's reach.
-class ChangedTouches final {
-    STACK_ALLOCATED();
-public:
-    // The touches corresponding to the particular change state this struct
-    // instance represents.
-    Member<TouchList> m_touches;
-
-    using EventTargetSet = HeapHashSet<Member<EventTarget>>;
-    // Set of targets involved in m_touches.
-    EventTargetSet m_targets;
-};
-
-} // namespace
-
-WebInputEventResult EventHandler::dispatchTouchEvents(const PlatformTouchEvent& event,
-    HeapVector<TouchInfo>& touchInfos, bool freshTouchEvents, bool allTouchReleased)
-{
-    // Build up the lists to use for the 'touches', 'targetTouches' and
-    // 'changedTouches' attributes in the JS event. See
-    // http://www.w3.org/TR/touch-events/#touchevent-interface for how these
-    // lists fit together.
-
-    // Holds the complete set of touches on the screen.
-    TouchList* touches = TouchList::create();
-
-    // A different view on the 'touches' list above, filtered and grouped by
-    // event target. Used for the 'targetTouches' list in the JS event.
-    using TargetTouchesHeapMap = HeapHashMap<EventTarget*, Member<TouchList>>;
-    TargetTouchesHeapMap touchesByTarget;
-
-    // Array of touches per state, used to assemble the 'changedTouches' list.
-    ChangedTouches changedTouches[PlatformTouchPoint::TouchStateEnd];
-
-    for (unsigned i = 0; i < touchInfos.size(); ++i) {
-        const TouchInfo& touchInfo = touchInfos[i];
-        const PlatformTouchPoint& point = touchInfo.point;
-        PlatformTouchPoint::TouchState pointState = point.state();
-
-        if (touchInfo.consumed)
-            continue;
-
-        Touch* touch = Touch::create(
-            touchInfo.targetFrame.get(),
-            touchInfo.touchTarget.get(),
-            point.id(),
-            point.screenPos(),
-            touchInfo.adjustedPagePoint,
-            touchInfo.adjustedRadius,
-            point.rotationAngle(),
-            point.force(),
-            touchInfo.region);
-
-        // Ensure this target's touch list exists, even if it ends up empty, so
-        // it can always be passed to TouchEvent::Create below.
-        TargetTouchesHeapMap::iterator targetTouchesIterator = touchesByTarget.find(touchInfo.touchTarget.get());
-        if (targetTouchesIterator == touchesByTarget.end()) {
-            touchesByTarget.set(touchInfo.touchTarget.get(), TouchList::create());
-            targetTouchesIterator = touchesByTarget.find(touchInfo.touchTarget.get());
-        }
-
-        // touches and targetTouches should only contain information about
-        // touches still on the screen, so if this point is released or
-        // cancelled it will only appear in the changedTouches list.
-        if (pointState != PlatformTouchPoint::TouchReleased && pointState != PlatformTouchPoint::TouchCancelled) {
-            touches->append(touch);
-            targetTouchesIterator->value->append(touch);
-        }
-
-        // Now build up the correct list for changedTouches.
-        // Note that  any touches that are in the TouchStationary state (e.g. if
-        // the user had several points touched but did not move them all) should
-        // never be in the changedTouches list so we do not handle them
-        // explicitly here. See https://bugs.webkit.org/show_bug.cgi?id=37609
-        // for further discussion about the TouchStationary state.
-        if (pointState != PlatformTouchPoint::TouchStationary && touchInfo.knownTarget) {
-            ASSERT(pointState < PlatformTouchPoint::TouchStateEnd);
-            if (!changedTouches[pointState].m_touches)
-                changedTouches[pointState].m_touches = TouchList::create();
-            changedTouches[pointState].m_touches->append(touch);
-            changedTouches[pointState].m_targets.add(touchInfo.touchTarget);
-        }
-    }
-    if (allTouchReleased) {
-        m_touchSequenceDocument.clear();
-        m_touchSequenceUserGestureToken.clear();
-    }
-
-    WebInputEventResult eventResult = WebInputEventResult::NotHandled;
-
-    // Now iterate through the changedTouches list and m_targets within it, sending
-    // TouchEvents to the targets as required.
-    for (unsigned state = 0; state != PlatformTouchPoint::TouchStateEnd; ++state) {
-        if (!changedTouches[state].m_touches)
-            continue;
-
-        const AtomicString& eventName(touchEventNameForTouchPointState(static_cast<PlatformTouchPoint::TouchState>(state)));
-        for (const auto& eventTarget : changedTouches[state].m_targets) {
-            EventTarget* touchEventTarget = eventTarget;
-            TouchEvent* touchEvent = TouchEvent::create(
-                touches, touchesByTarget.get(touchEventTarget), changedTouches[state].m_touches.get(),
-                eventName, touchEventTarget->toNode()->document().domWindow(),
-                event.getModifiers(), event.cancelable(), event.causesScrollingIfUncanceled(), event.timestamp());
-
-            eventResult = mergeEventResult(eventResult, toWebInputEventResult(touchEventTarget->dispatchEvent(touchEvent)));
-        }
-    }
-
-    return eventResult;
-}
-
 WebInputEventResult EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleTouchEvent");
 
-    if (event.type() == PlatformEvent::TouchScrollStarted) {
-        m_pointerEventManager.blockTouchPointers();
-        return WebInputEventResult::HandledSystem;
-    }
-
-    const Vector<PlatformTouchPoint>& points = event.touchPoints();
-
-    bool newTouchSequence = true;
-    bool allTouchReleased = true;
-    for (unsigned i = 0; i < points.size(); ++i) {
-        const PlatformTouchPoint& point = points[i];
-
-        if (point.state() != PlatformTouchPoint::TouchPressed)
-            newTouchSequence = false;
-        if (point.state() != PlatformTouchPoint::TouchReleased && point.state() != PlatformTouchPoint::TouchCancelled)
-            allTouchReleased = false;
-    }
-    if (newTouchSequence) {
-        // Ideally we'd ASSERT !m_touchSequenceDocument here since we should
-        // have cleared the active document when we saw the last release. But we
-        // have some tests that violate this, ClusterFuzz could trigger it, and
-        // there may be cases where the browser doesn't reliably release all
-        // touches. http://crbug.com/345372 tracks this.
-        m_touchSequenceDocument.clear();
-        m_touchSequenceUserGestureToken.clear();
-    }
-
-    ASSERT(m_frame->view());
-    if (m_touchSequenceDocument && (!m_touchSequenceDocument->frame() || !m_touchSequenceDocument->frame()->view())) {
-        // If the active touch document has no frame or view, it's probably being destroyed
-        // so we can't dispatch events.
-        return WebInputEventResult::NotHandled;
-    }
-
-    // First do hit tests for any new touch points.
-    for (unsigned i = 0; i < points.size(); ++i) {
-        const PlatformTouchPoint& point = points[i];
-
-        // Touch events implicitly capture to the touched node, and don't change
-        // active/hover states themselves (Gesture events do). So we only need
-        // to hit-test on touchstart, and it can be read-only.
-        if (point.state() == PlatformTouchPoint::TouchPressed) {
-            HitTestRequest::HitTestRequestType hitType = HitTestRequest::TouchEvent | HitTestRequest::ReadOnly | HitTestRequest::Active;
-            LayoutPoint pagePoint = roundedLayoutPoint(m_frame->view()->rootFrameToContents(point.pos()));
-            HitTestResult result;
-            if (!m_touchSequenceDocument) {
-                result = hitTestResultAtPoint(pagePoint, hitType);
-            } else if (m_touchSequenceDocument->frame()) {
-                LayoutPoint framePoint = roundedLayoutPoint(m_touchSequenceDocument->frame()->view()->rootFrameToContents(point.pos()));
-                result = hitTestResultInFrame(m_touchSequenceDocument->frame(), framePoint, hitType);
-            } else {
-                continue;
-            }
-
-            Node* node = result.innerNode();
-            if (!node)
-                continue;
-
-            if (isHTMLCanvasElement(node)) {
-                std::pair<Element*, String> regionInfo = toHTMLCanvasElement(node)->getControlAndIdIfHitRegionExists(result.pointInInnerNodeFrame());
-                if (regionInfo.first)
-                    node = regionInfo.first;
-                m_regionForTouchID.set(point.id(), regionInfo.second);
-            }
-
-            // Touch events should not go to text nodes
-            if (node->isTextNode())
-                node = FlatTreeTraversal::parent(*node);
-
-            if (!m_touchSequenceDocument) {
-                // Keep track of which document should receive all touch events
-                // in the active sequence. This must be a single document to
-                // ensure we don't leak Nodes between documents.
-                m_touchSequenceDocument = &(result.innerNode()->document());
-                ASSERT(m_touchSequenceDocument->frame()->view());
-            }
-
-            // Ideally we'd ASSERT(!m_targetForTouchID.contains(point.id())
-            // since we shouldn't get a touchstart for a touch that's already
-            // down. However EventSender allows this to be violated and there's
-            // some tests that take advantage of it. There may also be edge
-            // cases in the browser where this happens.
-            // See http://crbug.com/345372.
-            m_targetForTouchID.set(point.id(), node);
-
-            TouchAction effectiveTouchAction = TouchActionUtil::computeEffectiveTouchAction(*node);
-            if (effectiveTouchAction != TouchActionAuto)
-                m_frame->page()->chromeClient().setTouchAction(effectiveTouchAction);
-        }
-    }
-
-    m_touchPressed = !allTouchReleased;
-
-    // If there's no document receiving touch events, or no handlers on the
-    // document set to receive the events, then we can skip all the rest of
-    // this work.
-    if (!m_touchSequenceDocument || !m_touchSequenceDocument->frameHost() || !hasTouchHandlers(m_touchSequenceDocument->frameHost()->eventHandlerRegistry()) || !m_touchSequenceDocument->frame()) {
-        if (allTouchReleased) {
-            m_touchSequenceDocument.clear();
-            m_touchSequenceUserGestureToken.clear();
-        }
-        return WebInputEventResult::NotHandled;
-    }
-
-    // Whether a touch should be considered a "user gesture" or not is a tricky question.
-    // https://docs.google.com/document/d/1oF1T3O7_E4t1PYHV6gyCwHxOi3ystm0eSL5xZu7nvOg/edit#
-    // TODO(rbyers): Disable user gesture in some cases but retain logging for now (crbug.com/582140).
-    OwnPtr<UserGestureIndicator> gestureIndicator;
-    if (event.touchPoints().size() == 1
-        && event.touchPoints()[0].state() == PlatformTouchPoint::TouchReleased
-        && !event.causesScrollingIfUncanceled()) {
-        // This is a touchend corresponding to a tap, definitely a user gesture.  So don't supply
-        // a UserGestureUtilizedCallback.
-        gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture));
-    } else {
-        // This is some other touch event that perhaps shouldn't be considered a user gesture.  So
-        // use a UserGestureUtilizedCallback to get metrics / deprecation warnings.
-        if (m_touchSequenceUserGestureToken)
-            gestureIndicator = adoptPtr(new UserGestureIndicator(m_touchSequenceUserGestureToken.release(), &m_touchSequenceDocument->frame()->eventHandler()));
-        else
-            gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture, &m_touchSequenceDocument->frame()->eventHandler()));
-        m_touchSequenceUserGestureToken = UserGestureIndicator::currentToken();
-    }
-
-    // Compute and store the common info used by both PointerEvent and TouchEvent.
-    HeapVector<TouchInfo> touchInfos(points.size());
-
-    for (unsigned i = 0; i < points.size(); ++i) {
-        const PlatformTouchPoint& point = points[i];
-        PlatformTouchPoint::TouchState pointState = point.state();
-        EventTarget* touchTarget = nullptr;
-        String regionID;
-
-        if (pointState == PlatformTouchPoint::TouchReleased || pointState == PlatformTouchPoint::TouchCancelled) {
-            // The target should be the original target for this touch, so get
-            // it from the hashmap. As it's a release or cancel we also remove
-            // it from the map.
-            touchTarget = m_targetForTouchID.take(point.id());
-            regionID = m_regionForTouchID.take(point.id());
-        } else {
-            // No hittest is performed on move or stationary, since the target
-            // is not allowed to change anyway.
-            touchTarget = m_targetForTouchID.get(point.id());
-            regionID = m_regionForTouchID.get(point.id());
-        }
-
-        LocalFrame* targetFrame = nullptr;
-        bool knownTarget = false;
-        if (touchTarget) {
-            Document& doc = touchTarget->toNode()->document();
-            // If the target node has moved to a new document while it was being touched,
-            // we can't send events to the new document because that could leak nodes
-            // from one document to another. See http://crbug.com/394339.
-            if (&doc == m_touchSequenceDocument.get()) {
-                targetFrame = doc.frame();
-                knownTarget = true;
-            }
-        }
-        if (!knownTarget) {
-            // If we don't have a target registered for the point it means we've
-            // missed our opportunity to do a hit test for it (due to some
-            // optimization that prevented blink from ever seeing the
-            // touchstart), or that the touch started outside the active touch
-            // sequence document. We should still include the touch in the
-            // Touches list reported to the application (eg. so it can
-            // differentiate between a one and two finger gesture), but we won't
-            // actually dispatch any events for it. Set the target to the
-            // Document so that there's some valid node here. Perhaps this
-            // should really be LocalDOMWindow, but in all other cases the target of
-            // a Touch is a Node so using the window could be a breaking change.
-            // Since we know there was no handler invoked, the specific target
-            // should be completely irrelevant to the application.
-            touchTarget = m_touchSequenceDocument;
-            targetFrame = m_touchSequenceDocument->frame();
-        }
-        ASSERT(targetFrame);
-
-        // pagePoint should always be in the target element's document coordinates.
-        FloatPoint pagePoint = targetFrame->view()->rootFrameToContents(point.pos());
-        float scaleFactor = 1.0f / targetFrame->pageZoomFactor();
-
-        TouchInfo& touchInfo = touchInfos[i];
-        touchInfo.point = point;
-        touchInfo.touchTarget = touchTarget;
-        touchInfo.targetFrame = targetFrame;
-        touchInfo.adjustedPagePoint = pagePoint.scaledBy(scaleFactor);
-        touchInfo.adjustedRadius = point.radius().scaledBy(scaleFactor);
-        touchInfo.knownTarget = knownTarget;
-        touchInfo.consumed = false;
-        touchInfo.region = regionID;
-    }
-
-    if (newTouchSequence)
-        m_pointerEventManager.unblockTouchPointers();
-    dispatchPointerEvents(event, touchInfos);
-    // Note that the disposition of any pointer events affects only the generation of touch
-    // events. If all pointer events were handled (and hence no touch events were fired), that
-    // is still equivalent to the touch events going unhandled because pointer event handler
-    // don't block scroll gesture generation.
-
-    // TODO(crbug.com/507408): If PE handlers always call preventDefault, we won't see TEs until after
-    // scrolling starts because the scrolling would suppress upcoming PEs. This sudden "break" in TE
-    // suppression can make the visible TEs inconsistent (e.g. touchmove without a touchstart).
-
-    return dispatchTouchEvents(event, touchInfos, newTouchSequence, allTouchReleased);
+    return m_pointerEventManager.handleTouchEvents(event);
 }
 
 void EventHandler::userGestureUtilized()