Return a enumeration of the state of handling of InputEvents.

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 898e7d53aeac75f92ae1735d289de4cfb5aceade..b56a0c0421ff4c2eae73ac5a5f62d95792904c15 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandler.cpp
@@ -42,6 +42,7 @@
 #include "core/editing/SelectionController.h"
 #include "core/events/DragEvent.h"
 #include "core/events/EventPath.h"
+#include "core/events/GestureEvent.h"
 #include "core/events/KeyboardEvent.h"
 #include "core/events/MouseEvent.h"
 #include "core/events/PointerEvent.h"
@@ -103,6 +104,36 @@ namespace blink {
 
 namespace {
 
+WebInputEventResult mergeEventResult(WebInputEventResult responseA, WebInputEventResult responseB)
+{
+    // The ordering of the enumeration is specific. There are times that
+    // multiple events fire and we need to combine them into a single
+    // result code. The enumeration is based on the level of consumption that
+    // is most significant. The enumeration is ordered with smaller specified
+    // numbers first. Examples of merged results are:
+    // (HandledApplication, HandledSystem) -> HandledSystem
+    // (NotHandled, HandledApplication) -> HandledApplication
+    static_assert(static_cast<int>(WebInputEventResult::NotHandled) == 0, "WebInputEventResult not ordered");
+    static_assert(static_cast<int>(WebInputEventResult::HandledSuppressed) < static_cast<int>(WebInputEventResult::HandledApplication), "WebInputEventResult not ordered");
+    static_assert(static_cast<int>(WebInputEventResult::HandledApplication) < static_cast<int>(WebInputEventResult::HandledSystem), "WebInputEventResult not ordered");
+    return static_cast<WebInputEventResult>(max(static_cast<int>(responseA), static_cast<int>(responseB)));
+}
+
+WebInputEventResult eventToEventResult(PassRefPtrWillBeRawPtr<Event> event, bool res)
+{
+    if (event->defaultPrevented())
+        return WebInputEventResult::HandledApplication;
+    if (event->defaultHandled())
+        return WebInputEventResult::HandledSystem;
+
+    // TODO(dtapuska): There are cases in the code where dispatchEvent
+    // returns false (indicated handled) but event is not marked
+    // as default handled or default prevented. crbug.com/560355
+    if (!res)
+        return WebInputEventResult::HandledSuppressed;
+    return WebInputEventResult::NotHandled;
+}
+
 bool isNodeInDocument(Node* n)
 {
     return n && n->inDocument();
@@ -400,7 +431,7 @@ void EventHandler::nodeWillBeRemoved(Node& nodeToBeRemoved)
     }
 }
 
-bool EventHandler::handleMousePressEvent(const MouseEventWithHitTestResults& event)
+WebInputEventResult EventHandler::handleMousePressEvent(const MouseEventWithHitTestResults& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMousePressEvent");
 
@@ -413,7 +444,7 @@ bool EventHandler::handleMousePressEvent(const MouseEventWithHitTestResults& eve
 
     if (FrameView* frameView = m_frame->view()) {
         if (frameView->isPointInScrollbarCorner(event.event().position()))
-            return false;
+            return WebInputEventResult::NotHandled;
     }
 
     bool singleClick = event.event().clickCount() <= 1;
@@ -428,7 +459,7 @@ bool EventHandler::handleMousePressEvent(const MouseEventWithHitTestResults& eve
         if (event.event().shiftKey() && singleClick) {
             m_svgPan = true;
             m_frame->document()->accessSVGExtensions().startPan(m_frame->view()->rootFrameToContents(event.event().position()));
-            return true;
+            return WebInputEventResult::HandledSystem;
         }
     }
 
@@ -455,10 +486,10 @@ bool EventHandler::handleMousePressEvent(const MouseEventWithHitTestResults& eve
     m_mouseDownMayStartAutoscroll = selectionController().mouseDownMayStartSelect()
         || (m_mousePressNode && m_mousePressNode->layoutBox() && m_mousePressNode->layoutBox()->canBeProgramaticallyScrolled());
 
-    return swallowEvent;
+    return swallowEvent ? WebInputEventResult::HandledSystem : WebInputEventResult::NotHandled;
 }
 
-bool EventHandler::handleMouseDraggedEvent(const MouseEventWithHitTestResults& event)
+WebInputEventResult EventHandler::handleMouseDraggedEvent(const MouseEventWithHitTestResults& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMouseDraggedEvent");
 
@@ -480,24 +511,24 @@ bool EventHandler::handleMouseDraggedEvent(const MouseEventWithHitTestResults& e
         m_mousePressed = false;
 
     if (!m_mousePressed)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     if (handleDrag(event, DragInitiator::Mouse))
-        return true;
+        return WebInputEventResult::HandledSystem;
 
     Node* targetNode = event.innerNode();
     if (!targetNode)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     LayoutObject* layoutObject = targetNode->layoutObject();
     if (!layoutObject) {
         Node* parent = ComposedTreeTraversal::parent(*targetNode);
         if (!parent)
-            return false;
+            return WebInputEventResult::NotHandled;
 
         layoutObject = parent->layoutObject();
         if (!layoutObject || !layoutObject->isListBox())
-            return false;
+            return WebInputEventResult::NotHandled;
     }
 
     m_mouseDownMayStartDrag = false;
@@ -510,7 +541,7 @@ bool EventHandler::handleMouseDraggedEvent(const MouseEventWithHitTestResults& e
     }
 
     selectionController().handleMouseDraggedEvent(event, m_mouseDownPos, m_dragStartPos, m_mousePressNode.get(), m_lastKnownMousePosition);
-    return true;
+    return WebInputEventResult::HandledSystem;
 }
 
 void EventHandler::updateSelectionForMouseDrag()
@@ -518,7 +549,7 @@ void EventHandler::updateSelectionForMouseDrag()
     selectionController().updateSelectionForMouseDrag(m_mousePressNode.get(), m_dragStartPos, m_lastKnownMousePosition);
 }
 
-bool EventHandler::handleMouseReleaseEvent(const MouseEventWithHitTestResults& event)
+WebInputEventResult EventHandler::handleMouseReleaseEvent(const MouseEventWithHitTestResults& event)
 {
     AutoscrollController* controller = autoscrollController();
     if (controller && controller->autoscrollInProgress())
@@ -531,7 +562,7 @@ bool EventHandler::handleMouseReleaseEvent(const MouseEventWithHitTestResults& e
     m_mouseDownMayStartDrag = false;
     m_mouseDownMayStartAutoscroll = false;
 
-    return selectionController().handleMouseReleaseEvent(event, m_dragStartPos);
+    return selectionController().handleMouseReleaseEvent(event, m_dragStartPos) ? WebInputEventResult::HandledSystem : WebInputEventResult::NotHandled;
 }
 
 #if OS(WIN)
@@ -948,7 +979,7 @@ static LayoutPoint contentPointFromRootFrame(LocalFrame* frame, const IntPoint&
     return view ? view->rootFrameToContents(pointInRootFrame) : pointInRootFrame;
 }
 
-bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
+WebInputEventResult EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMousePressEvent");
 
@@ -971,7 +1002,7 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
         m_mouseDownPos = view->rootFrameToContents(mouseEvent.position());
     } else {
         invalidateClick();
-        return false;
+        return WebInputEventResult::NotHandled;
     }
 
     HitTestRequest request(HitTestRequest::Active);
@@ -982,22 +1013,25 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
 
     if (!mev.innerNode()) {
         invalidateClick();
-        return false;
+        return WebInputEventResult::NotHandled;
     }
 
     m_mousePressNode = mev.innerNode();
 
     RefPtrWillBeRawPtr<LocalFrame> subframe = subframeForHitTestResult(mev);
-    if (subframe && passMousePressEventToSubframe(mev, subframe.get())) {
+    if (subframe) {
+        WebInputEventResult result = passMousePressEventToSubframe(mev, subframe.get());
         // Start capturing future events for this frame.  We only do this if we didn't clear
         // the m_mousePressed flag, which may happen if an AppKit widget entered a modal event loop.
+        // The capturing should be done only when the result indicates it
+        // has been handled. See crbug.com/269917
         m_capturesDragging = subframe->eventHandler().capturesDragging();
         if (m_mousePressed && m_capturesDragging) {
             m_capturingMouseEventsNode = mev.innerNode();
             m_eventHandlerWillResetCapturingMouseEventsNode = true;
         }
         invalidateClick();
-        return true;
+        return result;
     }
 
 #if OS(WIN)
@@ -1009,7 +1043,7 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
         // We invalidate the click when exiting pan scrolling so that we don't inadvertently navigate
         // away from the current page (e.g. the click was on a hyperlink). See <rdar://problem/6095023>.
         invalidateClick();
-        return true;
+        return WebInputEventResult::HandledSuppressed;
     }
 #endif
 
@@ -1024,13 +1058,13 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
             m_resizeScrollableArea->setInResizeMode(true);
             m_offsetFromResizeCorner = LayoutSize(m_resizeScrollableArea->offsetFromResizeCorner(p));
             invalidateClick();
-            return true;
+            return WebInputEventResult::HandledSuppressed;
         }
     }
 
     m_frame->selection().setCaretBlinkingSuspended(true);
 
-    bool swallowEvent = updatePointerTargetAndDispatchEvents(EventTypeNames::mousedown, mev.innerNode(), m_clickCount, mouseEvent);
+    WebInputEventResult eventResult = updatePointerTargetAndDispatchEvents(EventTypeNames::mousedown, mev.innerNode(), m_clickCount, mouseEvent);
 
     // m_selectionInitiationState is initialized after dispatching mousedown
     // event in order not to keep the selection by DOM APIs Because we can't
@@ -1041,8 +1075,9 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
     HitTestResult hitTestResult = hitTestResultInFrame(m_frame, documentPoint, HitTestRequest::ReadOnly);
     InputDeviceCapabilities* sourceCapabilities = mouseEvent.syntheticEventType() == PlatformMouseEvent::FromTouch ? InputDeviceCapabilities::firesTouchEventsSourceCapabilities() :
         InputDeviceCapabilities::doesntFireTouchEventsSourceCapabilities();
-    swallowEvent = swallowEvent || handleMouseFocus(MouseEventWithHitTestResults(mouseEvent, hitTestResult), sourceCapabilities);
-    m_capturesDragging = !swallowEvent || mev.scrollbar();
+    if (eventResult == WebInputEventResult::NotHandled)
+        eventResult = handleMouseFocus(MouseEventWithHitTestResults(mouseEvent, hitTestResult), sourceCapabilities);
+    m_capturesDragging = eventResult == WebInputEventResult::NotHandled || mev.scrollbar();
 
     // If the hit testing originally determined the event was in a scrollbar, refetch the MouseEventWithHitTestResults
     // in case the scrollbar widget was destroyed when the mouse event was handled.
@@ -1054,7 +1089,7 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
             m_lastScrollbarUnderMouse = nullptr;
     }
 
-    if (swallowEvent) {
+    if (eventResult != WebInputEventResult::NotHandled) {
         // scrollbars should get events anyway, even disabled controls might be scrollable
         passMousePressEventToScrollbar(mev);
     } else {
@@ -1064,9 +1099,9 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
         }
 
         if (passMousePressEventToScrollbar(mev))
-            swallowEvent = true;
+            eventResult = WebInputEventResult::HandledSystem;
         else
-            swallowEvent = handleMousePressEvent(mev);
+            eventResult = handleMousePressEvent(mev);
     }
 
     if (mev.hitTestResult().innerNode() && mouseEvent.button() == LeftButton) {
@@ -1076,7 +1111,7 @@ bool EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
         m_frame->chromeClient().onMouseDown(result.innerNode());
     }
 
-    return swallowEvent;
+    return eventResult;
 }
 
 static PaintLayer* layerForNode(Node* node)
@@ -1105,7 +1140,7 @@ ScrollableArea* EventHandler::associatedScrollableArea(const PaintLayer* layer)
     return nullptr;
 }
 
-bool EventHandler::handleMouseMoveEvent(const PlatformMouseEvent& event)
+WebInputEventResult EventHandler::handleMouseMoveEvent(const PlatformMouseEvent& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMouseMoveEvent");
 
@@ -1114,7 +1149,7 @@ bool EventHandler::handleMouseMoveEvent(const PlatformMouseEvent& event)
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
 
     HitTestResult hoveredNode = HitTestResult();
-    bool result = handleMouseMoveOrLeaveEvent(event, &hoveredNode);
+    WebInputEventResult result = handleMouseMoveOrLeaveEvent(event, &hoveredNode);
 
     Page* page = m_frame->page();
     if (!page)
@@ -1144,7 +1179,7 @@ void EventHandler::handleMouseLeaveEvent(const PlatformMouseEvent& event)
     handleMouseMoveOrLeaveEvent(event, 0, false, true);
 }
 
-bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEvent, HitTestResult* hoveredNode, bool onlyUpdateScrollbars, bool forceLeave)
+WebInputEventResult EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEvent, HitTestResult* hoveredNode, bool onlyUpdateScrollbars, bool forceLeave)
 {
     ASSERT(m_frame);
     ASSERT(m_frame->view());
@@ -1160,7 +1195,7 @@ bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEv
 
     if (m_svgPan) {
         m_frame->document()->accessSVGExtensions().updatePan(m_frame->view()->rootFrameToContents(m_lastKnownMousePosition));
-        return true;
+        return WebInputEventResult::HandledSuppressed;
     }
 
     if (m_frameSetBeingResized)
@@ -1169,7 +1204,7 @@ bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEv
     // Send events right to a scrollbar if the mouse is pressed.
     if (m_lastScrollbarUnderMouse && m_mousePressed) {
         m_lastScrollbarUnderMouse->mouseMoved(mouseEvent);
-        return true;
+        return WebInputEventResult::HandledSystem;
     }
 
     // Mouse events simulated from touch should not hit-test again.
@@ -1212,10 +1247,10 @@ bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEv
 
         updateLastScrollbarUnderMouse(scrollbar, !m_mousePressed);
         if (onlyUpdateScrollbars)
-            return true;
+            return WebInputEventResult::HandledSuppressed;
     }
 
-    bool swallowEvent = false;
+    WebInputEventResult eventResult = WebInputEventResult::NotHandled;
     RefPtrWillBeRawPtr<LocalFrame> newSubframe = m_capturingMouseEventsNode.get() ? subframeForTargetNode(m_capturingMouseEventsNode.get()) : subframeForHitTestResult(mev);
 
     // We want mouseouts to happen first, from the inside out.  First send a move event to the last subframe so that it will fire mouseouts.
@@ -1229,7 +1264,7 @@ bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEv
         // Event dispatch in updateMouseEventTargetNode may have caused the subframe of the target
         // node to be detached from its FrameView, in which case the event should not be passed.
         if (newSubframe->view())
-            swallowEvent |= passMouseMoveEventToSubframe(mev, newSubframe.get(), hoveredNode);
+            eventResult = passMouseMoveEventToSubframe(mev, newSubframe.get(), hoveredNode);
     } else {
         if (scrollbar && !m_mousePressed)
             scrollbar->mouseMoved(mouseEvent); // Handle hover effects on platforms that support visual feedback on scrollbar hovering.
@@ -1243,15 +1278,14 @@ bool EventHandler::handleMouseMoveOrLeaveEvent(const PlatformMouseEvent& mouseEv
 
     m_lastMouseMoveEventSubframe = newSubframe;
 
-    if (swallowEvent)
-        return true;
-
-    swallowEvent = updatePointerTargetAndDispatchEvents(EventTypeNames::mousemove, mev.innerNode(), 0, mouseEvent);
+    if (eventResult != WebInputEventResult::NotHandled)
+        return eventResult;
 
-    if (!swallowEvent)
-        swallowEvent = handleMouseDraggedEvent(mev);
+    eventResult = updatePointerTargetAndDispatchEvents(EventTypeNames::mousemove, mev.innerNode(), 0, mouseEvent);
+    if (eventResult != WebInputEventResult::NotHandled)
+        return eventResult;
 
-    return swallowEvent;
+    return handleMouseDraggedEvent(mev);
 }
 
 void EventHandler::invalidateClick()
@@ -1270,7 +1304,7 @@ static ContainerNode* parentForClickEvent(const Node& node)
     return ComposedTreeTraversal::parent(node);
 }
 
-bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
+WebInputEventResult EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMouseReleaseEvent");
 
@@ -1296,7 +1330,7 @@ bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
     if (m_svgPan) {
         m_svgPan = false;
         m_frame->document()->accessSVGExtensions().updatePan(m_frame->view()->rootFrameToContents(m_lastKnownMousePosition));
-        return true;
+        return WebInputEventResult::HandledSuppressed;
     }
 
     if (m_frameSetBeingResized)
@@ -1317,10 +1351,10 @@ bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
     LocalFrame* subframe = m_capturingMouseEventsNode.get() ? subframeForTargetNode(m_capturingMouseEventsNode.get()) : subframeForHitTestResult(mev);
     if (m_eventHandlerWillResetCapturingMouseEventsNode)
         m_capturingMouseEventsNode = nullptr;
-    if (subframe && passMouseReleaseEventToSubframe(mev, subframe))
-        return true;
+    if (subframe)
+        return passMouseReleaseEventToSubframe(mev, subframe);
 
-    bool swallowUpEvent = updatePointerTargetAndDispatchEvents(EventTypeNames::mouseup, mev.innerNode(), m_clickCount, mouseEvent);
+    WebInputEventResult eventResult = updatePointerTargetAndDispatchEvents(EventTypeNames::mouseup, mev.innerNode(), m_clickCount, mouseEvent);
 
     // TODO(crbug/545647): This state should reset with pointercancel too.
     m_preventMouseEventForPointerTypeMouse = false;
@@ -1332,7 +1366,7 @@ bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
         contextMenuEvent = true;
 #endif
 
-    bool swallowClickEvent = false;
+    WebInputEventResult clickEventResult = WebInputEventResult::NotHandled;
     if (m_clickCount > 0 && !contextMenuEvent && mev.innerNode() && m_clickNode && mev.innerNode()->canParticipateInComposedTree() && m_clickNode->canParticipateInComposedTree()) {
         // Updates distribution because a 'mouseup' event listener can make the
         // tree dirty at dispatchMouseEvent() invocation above.
@@ -1347,8 +1381,10 @@ bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
             // because the mouseup dispatch above has already updated it
             // correctly. Moreover, clickTargetNode is different from
             // mev.innerNode at drag-release.
-            clickTargetNode->dispatchMouseEvent(mouseEvent,
-                EventTypeNames::click, m_clickCount);
+            if (clickTargetNode->dispatchMouseEvent(mouseEvent,

[kotenkov, 2016/01/12 20:55:00]

There should be a negation here: |EventTarget::dispatchEvent()| returns true if
default was not prevented.
It doesn't affect anything in today's code, because the return value of this
function is ignored.

[dtapuska, 2016/01/12 21:06:48]

Thanks for the find; you are correct. This is in fact fixed in a follow up
change here https://codereview.chromium.org/1479923002/ that I need to get back
to working on.

+                EventTypeNames::click, m_clickCount)) {
+                clickEventResult = WebInputEventResult::HandledApplication;
+            }
         }
     }
 
@@ -1357,22 +1393,21 @@ bool EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
         m_resizeScrollableArea = nullptr;
     }
 
-    bool swallowMouseReleaseEvent = false;
-    if (!swallowUpEvent)
-        swallowMouseReleaseEvent = handleMouseReleaseEvent(mev);
+    if (eventResult == WebInputEventResult::NotHandled)
+        eventResult = handleMouseReleaseEvent(mev);
 
     invalidateClick();
 
-    return swallowUpEvent || swallowClickEvent || swallowMouseReleaseEvent;
+    return mergeEventResult(clickEventResult, eventResult);
 }
 
-bool EventHandler::dispatchDragEvent(const AtomicString& eventType, Node* dragTarget, const PlatformMouseEvent& event, DataTransfer* dataTransfer)
+WebInputEventResult EventHandler::dispatchDragEvent(const AtomicString& eventType, Node* dragTarget, const PlatformMouseEvent& event, DataTransfer* dataTransfer)
 {
     FrameView* view = m_frame->view();
 
     // FIXME: We might want to dispatch a dragleave even if the view is gone.
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     RefPtrWillBeRawPtr<DragEvent> me = DragEvent::create(eventType,
         true, true, m_frame->document()->domWindow(),
@@ -1381,8 +1416,8 @@ bool EventHandler::dispatchDragEvent(const AtomicString& eventType, Node* dragTa
         event.modifiers(),
         0, MouseEvent::platformModifiersToButtons(event.modifiers()), nullptr, event.timestamp(), dataTransfer, event.syntheticEventType());
 
-    dragTarget->dispatchEvent(me.get());
-    return me->defaultPrevented();
+    bool dispatchResult = dragTarget->dispatchEvent(me.get());
+    return eventToEventResult(me, dispatchResult);
 }
 
 static bool targetIsFrame(Node* target, LocalFrame*& frame)
@@ -1437,12 +1472,12 @@ static bool findDropZone(Node* target, DataTransfer* dataTransfer)
     return false;
 }
 
-bool EventHandler::updateDragAndDrop(const PlatformMouseEvent& event, DataTransfer* dataTransfer)
+WebInputEventResult EventHandler::updateDragAndDrop(const PlatformMouseEvent& event, DataTransfer* dataTransfer)
 {
-    bool accept = false;
+    WebInputEventResult eventResult = WebInputEventResult::NotHandled;
 
     if (!m_frame->view())
-        return false;
+        return eventResult;
 
     HitTestRequest request(HitTestRequest::ReadOnly);
     MouseEventWithHitTestResults mev = prepareMouseEvent(request, event);
@@ -1464,21 +1499,21 @@ bool EventHandler::updateDragAndDrop(const PlatformMouseEvent& event, DataTransf
         LocalFrame* targetFrame;
         if (targetIsFrame(newTarget.get(), targetFrame)) {
             if (targetFrame)
-                accept = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
+                eventResult = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
         } else if (newTarget) {
             // As per section 7.9.4 of the HTML 5 spec., we must always fire a drag event before firing a dragenter, dragleave, or dragover event.
             if (dragState().m_dragSrc) {
                 // for now we don't care if event handler cancels default behavior, since there is none
                 dispatchDragSrcEvent(EventTypeNames::drag, event);
             }
-            accept = dispatchDragEvent(EventTypeNames::dragenter, newTarget.get(), event, dataTransfer);
-            if (!accept)
-                accept = findDropZone(newTarget.get(), dataTransfer);
+            eventResult = dispatchDragEvent(EventTypeNames::dragenter, newTarget.get(), event, dataTransfer);
+            if (eventResult == WebInputEventResult::NotHandled && findDropZone(newTarget.get(), dataTransfer))
+                eventResult = WebInputEventResult::HandledSystem;
         }
 
         if (targetIsFrame(m_dragTarget.get(), targetFrame)) {
             if (targetFrame)
-                accept = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
+                eventResult = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
         } else if (m_dragTarget) {
             dispatchDragEvent(EventTypeNames::dragleave, m_dragTarget.get(), event, dataTransfer);
         }
@@ -1492,22 +1527,22 @@ bool EventHandler::updateDragAndDrop(const PlatformMouseEvent& event, DataTransf
         LocalFrame* targetFrame;
         if (targetIsFrame(newTarget.get(), targetFrame)) {
             if (targetFrame)
-                accept = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
+                eventResult = targetFrame->eventHandler().updateDragAndDrop(event, dataTransfer);
         } else if (newTarget) {
             // Note, when dealing with sub-frames, we may need to fire only a dragover event as a drag event may have been fired earlier.
             if (!m_shouldOnlyFireDragOverEvent && dragState().m_dragSrc) {
                 // for now we don't care if event handler cancels default behavior, since there is none
                 dispatchDragSrcEvent(EventTypeNames::drag, event);
             }
-            accept = dispatchDragEvent(EventTypeNames::dragover, newTarget.get(), event, dataTransfer);
-            if (!accept)
-                accept = findDropZone(newTarget.get(), dataTransfer);
+            eventResult = dispatchDragEvent(EventTypeNames::dragover, newTarget.get(), event, dataTransfer);
+            if (eventResult == WebInputEventResult::NotHandled && findDropZone(newTarget.get(), dataTransfer))
+                eventResult = WebInputEventResult::HandledSystem;
             m_shouldOnlyFireDragOverEvent = false;
         }
     }
     m_dragTarget = newTarget;
 
-    return accept;
+    return eventResult;
 }
 
 void EventHandler::cancelDragAndDrop(const PlatformMouseEvent& event, DataTransfer* dataTransfer)
@@ -1524,18 +1559,18 @@ void EventHandler::cancelDragAndDrop(const PlatformMouseEvent& event, DataTransf
     clearDragState();
 }
 
-bool EventHandler::performDragAndDrop(const PlatformMouseEvent& event, DataTransfer* dataTransfer)
+WebInputEventResult EventHandler::performDragAndDrop(const PlatformMouseEvent& event, DataTransfer* dataTransfer)
 {
     LocalFrame* targetFrame;
-    bool preventedDefault = false;
+    WebInputEventResult result = WebInputEventResult::NotHandled;
     if (targetIsFrame(m_dragTarget.get(), targetFrame)) {
         if (targetFrame)
-            preventedDefault = targetFrame->eventHandler().performDragAndDrop(event, dataTransfer);
+            result = targetFrame->eventHandler().performDragAndDrop(event, dataTransfer);
     } else if (m_dragTarget.get()) {
-        preventedDefault = dispatchDragEvent(EventTypeNames::drop, m_dragTarget.get(), event, dataTransfer);
+        result = dispatchDragEvent(EventTypeNames::drop, m_dragTarget.get(), event, dataTransfer);
     }
     clearDragState();
-    return preventedDefault;
+    return result;
 }
 
 void EventHandler::clearDragState()
@@ -1612,16 +1647,17 @@ void EventHandler::updateMouseEventTargetNode(Node* targetNode, const PlatformMo
         sendMouseEventsForNodeTransition(lastNodeUnderMouse.get(), m_nodeUnderMouse.get(), mouseEvent);
 }
 
-bool EventHandler::dispatchPointerEvent(Node* target, const AtomicString& eventType,
+WebInputEventResult EventHandler::dispatchPointerEvent(Node* target, const AtomicString& eventType,
     const PlatformMouseEvent& mouseEvent, Node* relatedTarget)
 {
     if (!RuntimeEnabledFeatures::pointerEventEnabled())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     RefPtrWillBeRawPtr<PointerEvent> pointerEvent = PointerEvent::create(eventType, true,
         mouseEvent, relatedTarget, m_frame->document()->domWindow());
-    target->dispatchEvent(pointerEvent.get());
-    return pointerEvent->defaultPrevented() || pointerEvent->defaultHandled();
+
+    bool dispatchResult = target->dispatchEvent(pointerEvent.get());
+    return eventToEventResult(pointerEvent, dispatchResult);
 }
 
 void EventHandler::sendMouseEventsForNodeTransition(Node* exitedNode, Node* enteredNode,
@@ -1727,14 +1763,19 @@ void EventHandler::sendMouseEventsForNodeTransition(Node* exitedNode, Node* ente
     }
 }
 
-bool EventHandler::dispatchMouseEvent(const AtomicString& eventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
+WebInputEventResult EventHandler::dispatchMouseEvent(const AtomicString& eventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
 {
     updateMouseEventTargetNode(targetNode, mouseEvent);
-    return m_nodeUnderMouse && !m_nodeUnderMouse->dispatchMouseEvent(mouseEvent, eventType, clickCount);
+    if (!m_nodeUnderMouse)
+        return WebInputEventResult::NotHandled;
+
+    RefPtrWillBeRawPtr<MouseEvent> event = MouseEvent::create(eventType, m_nodeUnderMouse->document().domWindow(), mouseEvent, clickCount, nullptr);
+    bool dispatchResult = m_nodeUnderMouse->dispatchEvent(event);
+    return eventToEventResult(event, dispatchResult);
 }
 
 // TODO(mustaq): Make PE drive ME dispatch & bookkeeping in EventHandler.
-bool EventHandler::updatePointerTargetAndDispatchEvents(const AtomicString& mouseEventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
+WebInputEventResult EventHandler::updatePointerTargetAndDispatchEvents(const AtomicString& mouseEventType, Node* targetNode, int clickCount, const PlatformMouseEvent& mouseEvent)
 {
     ASSERT(mouseEventType == EventTypeNames::mousedown
         || mouseEventType == EventTypeNames::mousemove
@@ -1742,29 +1783,31 @@ bool EventHandler::updatePointerTargetAndDispatchEvents(const AtomicString& mous
 
     updateMouseEventTargetNode(targetNode, mouseEvent);
     if (!m_nodeUnderMouse)
-        return false;
+        return WebInputEventResult::NotHandled;
 
-    bool swallowEvent = dispatchPointerEvent(m_nodeUnderMouse.get(),
+    WebInputEventResult result = dispatchPointerEvent(m_nodeUnderMouse.get(),
         pointerEventNameForMouseEventName(mouseEventType),
         mouseEvent);
 
-    if (swallowEvent && mouseEventType == EventTypeNames::mousedown) {
+    if (result != WebInputEventResult::NotHandled && mouseEventType == EventTypeNames::mousedown) {
         m_preventMouseEventForPointerTypeMouse = true;
     }
 
     if (!m_preventMouseEventForPointerTypeMouse) {
-        swallowEvent |= !m_nodeUnderMouse->dispatchMouseEvent(mouseEvent, mouseEventType, clickCount);
+        RefPtrWillBeRawPtr<MouseEvent> event = MouseEvent::create(mouseEventType, m_nodeUnderMouse->document().domWindow(), mouseEvent, clickCount, nullptr);
+        bool dispatchResult = m_nodeUnderMouse->dispatchEvent(event);
+        result = mergeEventResult(result, eventToEventResult(event, dispatchResult));
     }
 
-    return swallowEvent;
+    return result;
 }
 
-bool EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targetedEvent, InputDeviceCapabilities* sourceCapabilities)
+WebInputEventResult EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targetedEvent, InputDeviceCapabilities* sourceCapabilities)
 {
     // If clicking on a frame scrollbar, do not mess up with content focus.
     if (targetedEvent.hitTestResult().scrollbar() && m_frame->contentLayoutObject()) {
         if (targetedEvent.hitTestResult().scrollbar()->scrollableArea() == m_frame->contentLayoutObject()->scrollableArea())
-            return false;
+            return WebInputEventResult::NotHandled;
     }
 
     // The layout needs to be up to date to determine if an element is focusable.
@@ -1775,7 +1818,7 @@ bool EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targeted
         element = m_nodeUnderMouse->isElementNode() ? toElement(m_nodeUnderMouse) : m_nodeUnderMouse->parentOrShadowHostElement();
     for (; element; element = element->parentOrShadowHostElement()) {
         if (element->isFocusable() && element->isFocusedElementInDocument())
-            return false;
+            return WebInputEventResult::NotHandled;
         if (element->isMouseFocusable())
             break;
     }
@@ -1791,14 +1834,14 @@ bool EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targeted
         // |isNodeFullyContained()|.
         if (createRange(m_frame->selection().selection().toNormalizedEphemeralRange())->isNodeFullyContained(*element)
             && element->isDescendantOf(m_frame->document()->focusedElement()))
-            return false;
+            return WebInputEventResult::NotHandled;
     }
 
 
     // Only change the focus when clicking scrollbars if it can transfered to a
     // mouse focusable node.
     if (!element && targetedEvent.hitTestResult().scrollbar())
-        return true;
+        return WebInputEventResult::HandledSystem;
 
     if (Page* page = m_frame->page()) {
         // If focus shift is blocked, we eat the event. Note we should never
@@ -1806,20 +1849,20 @@ bool EventHandler::handleMouseFocus(const MouseEventWithHitTestResults& targeted
         // default behavior).
         if (element) {
             if (slideFocusOnShadowHostIfNecessary(*element))
-                return true;
+                return WebInputEventResult::HandledSystem;
             if (!page->focusController().setFocusedElement(element, m_frame, FocusParams(SelectionBehaviorOnFocus::None, WebFocusTypeMouse, sourceCapabilities)))
-                return true;
+                return WebInputEventResult::HandledSystem;
         } else {
             // We call setFocusedElement even with !element in order to blur
             // current focus element when a link is clicked; this is expected by
             // some sites that rely on onChange handlers running from form
             // fields before the button click is processed.
             if (!page->focusController().setFocusedElement(nullptr, m_frame, FocusParams(SelectionBehaviorOnFocus::None, WebFocusTypeNone, sourceCapabilities)))
-                return true;
+                return WebInputEventResult::HandledSystem;
         }
     }
 
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
 bool EventHandler::slideFocusOnShadowHostIfNecessary(const Element& element)
@@ -1880,24 +1923,18 @@ ScrollResult scrollAreaWithWheelEvent(const PlatformWheelEvent& event, Scrollabl
 
 } // namespace
 
-bool EventHandler::handleWheelEvent(const PlatformWheelEvent& event)
+WebInputEventResult EventHandler::handleWheelEvent(const PlatformWheelEvent& event)
 {
-#define RETURN_WHEEL_EVENT_HANDLED() \
-    { \
-        setFrameWasScrolledByUser(); \
-        return true; \
-    }
-
     Document* doc = m_frame->document();
 
     if (!doc->layoutView())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
 
     FrameView* view = m_frame->view();
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     LayoutPoint vPoint = view->rootFrameToContents(event.position());
 
@@ -1920,33 +1957,41 @@ bool EventHandler::handleWheelEvent(const PlatformWheelEvent& event)
         LayoutObject* target = node->layoutObject();
 
         if (isOverWidget && target && target->isLayoutPart()) {
-            Widget* widget = toLayoutPart(target)->widget();
-            if (widget && passWheelEventToWidget(event, *widget))
-                RETURN_WHEEL_EVENT_HANDLED();
+            if (Widget* widget = toLayoutPart(target)->widget()) {
+                WebInputEventResult result = passWheelEventToWidget(event, *widget);
+                if (result != WebInputEventResult::NotHandled) {
+                    setFrameWasScrolledByUser();
+                    return result;
+                }
+            }
         }
 
-        if (node && !node->dispatchWheelEvent(event))
-            RETURN_WHEEL_EVENT_HANDLED();
+        RefPtrWillBeRawPtr<Event> domEvent = WheelEvent::create(event, node->document().domWindow());
+        if (!node->dispatchEvent(domEvent)) {
+            setFrameWasScrolledByUser();
+            return eventToEventResult(domEvent, false);
+        }
     }
 
     // We do another check on the frame view because the event handler can run
     // JS which results in the frame getting destroyed.
     view = m_frame->view();
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     // Wheel events which do not scroll are used to trigger zooming.
     if (!event.canScroll())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     ScrollResult scrollResult = scrollAreaWithWheelEvent(event, *view->scrollableArea());
     if (m_frame->settings() && m_frame->settings()->reportWheelOverscroll())
         handleOverscroll(scrollResult);
-    if (scrollResult.didScroll())
-        RETURN_WHEEL_EVENT_HANDLED();
+    if (scrollResult.didScroll()) {
+        setFrameWasScrolledByUser();
+        return WebInputEventResult::HandledSystem;
+    }
 
-    return false;
-#undef RETURN_WHEEL_EVENT_HANDLED
+    return WebInputEventResult::NotHandled;
 }
 
 void EventHandler::defaultWheelEventHandler(Node* startNode, WheelEvent* wheelEvent)
@@ -1977,27 +2022,27 @@ void EventHandler::defaultWheelEventHandler(Node* startNode, WheelEvent* wheelEv
     m_previousWheelScrolledNode = stopNode;
 }
 
-bool EventHandler::handleGestureShowPress()
+WebInputEventResult EventHandler::handleGestureShowPress()
 {
     m_lastShowPressTimestamp = WTF::monotonicallyIncreasingTime();
 
     FrameView* view = m_frame->view();
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
     if (ScrollAnimatorBase* scrollAnimator = view->existingScrollAnimator())
         scrollAnimator->cancelAnimations();
     const FrameView::ScrollableAreaSet* areas = view->scrollableAreas();
     if (!areas)
-        return false;
+        return WebInputEventResult::NotHandled;
     for (const ScrollableArea* scrollableArea : *areas) {
         ScrollAnimatorBase* animator = scrollableArea->existingScrollAnimator();
         if (animator)
             animator->cancelAnimations();
     }
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
-bool EventHandler::handleGestureEvent(const PlatformGestureEvent& gestureEvent)
+WebInputEventResult EventHandler::handleGestureEvent(const PlatformGestureEvent& gestureEvent)
 {
     // Propagation to inner frames is handled below this function.
     ASSERT(m_frame == m_frame->localFrameRoot());
@@ -2014,7 +2059,7 @@ bool EventHandler::handleGestureEvent(const PlatformGestureEvent& gestureEvent)
     return handleGestureEvent(targetedEvent);
 }
 
-bool EventHandler::handleGestureEvent(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::handleGestureEvent(const GestureEventWithHitTestResults& targetedEvent)
 {
     TRACE_EVENT0("input", "EventHandler::handleGestureEvent");
 
@@ -2037,7 +2082,7 @@ bool EventHandler::handleGestureEvent(const GestureEventWithHitTestResults& targ
     return handleGestureEventInFrame(targetedEvent);
 }
 
-bool EventHandler::handleGestureEventInFrame(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::handleGestureEventInFrame(const GestureEventWithHitTestResults& targetedEvent)
 {
     ASSERT(!targetedEvent.event().isScrollEvent());
 
@@ -2050,11 +2095,16 @@ bool EventHandler::handleGestureEventInFrame(const GestureEventWithHitTestResult
         if (gestureEvent.type() == PlatformEvent::GestureTapDown && eventSwallowed)
             m_scrollbarHandlingScrollGesture = scrollbar;
         if (eventSwallowed)
-            return true;
+            return WebInputEventResult::HandledSuppressed;
     }
 
-    if (eventTarget && eventTarget->dispatchGestureEvent(gestureEvent))
-        return true;
+    if (eventTarget) {
+        RefPtrWillBeRawPtr<GestureEvent> gestureDomEvent = GestureEvent::create(eventTarget->document().domWindow(), gestureEvent);
+        // TODO(dtapuska): dispatchEvent is inverted for Gesture Events
+        // crbug.com/560357
+        if (gestureDomEvent.get() && eventTarget->dispatchEvent(gestureDomEvent))
+            return eventToEventResult(gestureDomEvent, false);
+    }
 
     switch (gestureEvent.type()) {
     case PlatformEvent::GestureTap:
@@ -2078,10 +2128,10 @@ bool EventHandler::handleGestureEventInFrame(const GestureEventWithHitTestResult
         ASSERT_NOT_REACHED();
     }
 
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
-bool EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureEvent)
+WebInputEventResult EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureEvent)
 {
     TRACE_EVENT0("input", "EventHandler::handleGestureScrollEvent");
 
@@ -2095,7 +2145,7 @@ bool EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureE
     if (!eventTarget) {
         Document* document = m_frame->document();
         if (!document->layoutView())
-            return false;
+            return WebInputEventResult::NotHandled;
 
         FrameView* view = m_frame->view();
         LayoutPoint viewPoint = view->rootFrameToContents(gestureEvent.position());
@@ -2121,15 +2171,18 @@ bool EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureE
             m_scrollbarHandlingScrollGesture = nullptr;
         }
         if (eventSwallowed)
-            return true;
+            return WebInputEventResult::HandledSuppressed;
     }
 
     if (eventTarget) {
-        bool eventSwallowed = handleScrollGestureOnResizer(eventTarget.get(), gestureEvent);
-        if (!eventSwallowed)
-            eventSwallowed = eventTarget->dispatchGestureEvent(gestureEvent);
-        if (eventSwallowed)
-            return true;
+        if (handleScrollGestureOnResizer(eventTarget.get(), gestureEvent))
+            return WebInputEventResult::HandledSuppressed;
+
+        RefPtrWillBeRawPtr<GestureEvent> gestureDomEvent = GestureEvent::create(eventTarget->document().domWindow(), gestureEvent);
+        // TODO(dtapuska): dispatchEvent is inverted for Gesture Events
+        // crbug.com/560357
+        if (gestureDomEvent.get() && eventTarget->dispatchEvent(gestureDomEvent))
+            return eventToEventResult(gestureDomEvent, false);
     }
 
     switch (gestureEvent.type()) {
@@ -2143,14 +2196,14 @@ bool EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureE
     case PlatformEvent::GesturePinchBegin:
     case PlatformEvent::GesturePinchEnd:
     case PlatformEvent::GesturePinchUpdate:
-        return false;
+        return WebInputEventResult::NotHandled;
     default:
         ASSERT_NOT_REACHED();
-        return false;
+        return WebInputEventResult::NotHandled;
     }
 }
 
-bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::handleGestureTap(const GestureEventWithHitTestResults& targetedEvent)
 {
     RefPtrWillBeRawPtr<FrameView> frameView(m_frame->view());
     const PlatformGestureEvent& gestureEvent = targetedEvent.event();
@@ -2200,12 +2253,12 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
         LeftButton, PlatformEvent::MousePressed, gestureEvent.tapCount(),
         static_cast<PlatformEvent::Modifiers>(modifiers | PlatformEvent::LeftButtonDown),
         PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
-    bool swallowMouseDownEvent = dispatchMouseEvent(EventTypeNames::mousedown, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseDown);
+    WebInputEventResult mouseDownEventResult = dispatchMouseEvent(EventTypeNames::mousedown, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseDown);
     selectionController().initializeSelectionState();
-    if (!swallowMouseDownEvent)
-        swallowMouseDownEvent = handleMouseFocus(MouseEventWithHitTestResults(fakeMouseDown, currentHitTest), InputDeviceCapabilities::firesTouchEventsSourceCapabilities());
-    if (!swallowMouseDownEvent)
-        swallowMouseDownEvent = handleMousePressEvent(MouseEventWithHitTestResults(fakeMouseDown, currentHitTest));
+    if (mouseDownEventResult == WebInputEventResult::NotHandled)
+        mouseDownEventResult = handleMouseFocus(MouseEventWithHitTestResults(fakeMouseDown, currentHitTest), InputDeviceCapabilities::firesTouchEventsSourceCapabilities());
+    if (mouseDownEventResult == WebInputEventResult::NotHandled)
+        mouseDownEventResult = handleMousePressEvent(MouseEventWithHitTestResults(fakeMouseDown, currentHitTest));
 
     if (currentHitTest.innerNode()) {
         ASSERT(gestureEvent.type() == PlatformEvent::GestureTap);
@@ -2226,9 +2279,9 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
         LeftButton, PlatformEvent::MouseReleased, gestureEvent.tapCount(),
         static_cast<PlatformEvent::Modifiers>(modifiers),
         PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
-    bool swallowMouseUpEvent = dispatchMouseEvent(EventTypeNames::mouseup, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseUp);
+    WebInputEventResult mouseUpEventResult = dispatchMouseEvent(EventTypeNames::mouseup, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseUp);
 
-    bool swallowClickEvent = false;
+    WebInputEventResult clickEventResult = WebInputEventResult::NotHandled;
     if (m_clickNode) {
         if (currentHitTest.innerNode()) {
             // Updates distribution because a mouseup (or mousedown) event listener can make the
@@ -2238,26 +2291,26 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
             // because commonAncestor() will exit early if their documents are different.
             m_clickNode->updateDistribution();
             Node* clickTargetNode = currentHitTest.innerNode()->commonAncestor(*m_clickNode, parentForClickEvent);
-            swallowClickEvent = dispatchMouseEvent(EventTypeNames::click, clickTargetNode, gestureEvent.tapCount(), fakeMouseUp);
+            clickEventResult = dispatchMouseEvent(EventTypeNames::click, clickTargetNode, gestureEvent.tapCount(), fakeMouseUp);
         }
         m_clickNode = nullptr;
     }
 
-    if (!swallowMouseUpEvent)
-        swallowMouseUpEvent = handleMouseReleaseEvent(MouseEventWithHitTestResults(fakeMouseUp, currentHitTest));
+    if (mouseUpEventResult == WebInputEventResult::NotHandled)
+        mouseUpEventResult = handleMouseReleaseEvent(MouseEventWithHitTestResults(fakeMouseUp, currentHitTest));
 
-    bool swallowed = swallowMouseDownEvent | swallowMouseUpEvent | swallowClickEvent;
-    if (!swallowed && tappedNode && m_frame->page()) {
+    WebInputEventResult eventResult = mergeEventResult(mergeEventResult(mouseDownEventResult, mouseUpEventResult), clickEventResult);
+    if (eventResult == WebInputEventResult::NotHandled && tappedNode && m_frame->page()) {
         bool domTreeChanged = preDispatchDomTreeVersion != m_frame->document()->domTreeVersion();
         bool styleChanged = preDispatchStyleVersion != m_frame->document()->styleVersion();
 
         IntPoint tappedPositionInViewport = m_frame->page()->frameHost().visualViewport().rootFrameToViewport(tappedPosition);
         m_frame->chromeClient().showUnhandledTapUIIfNeeded(tappedPositionInViewport, tappedNode.get(), domTreeChanged || styleChanged);
     }
-    return swallowed;
+    return eventResult;
 }
 
-bool EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults& targetedEvent)
 {
     const PlatformGestureEvent& gestureEvent = targetedEvent.event();
     IntPoint adjustedPoint = gestureEvent.position();
@@ -2286,7 +2339,7 @@ bool EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults&
         RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
         if (handleDrag(mev, DragInitiator::Touch)) {
             m_longTapShouldInvokeContextMenu = true;
-            return true;
+            return WebInputEventResult::HandledSystem;
         }
     }
 
@@ -2295,13 +2348,13 @@ bool EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults&
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
     if (selectionController().handleGestureLongPress(gestureEvent, result)) {
         focusDocumentView();
-        return true;
+        return WebInputEventResult::HandledSystem;
     }
 
     return sendContextMenuEventForGesture(targetedEvent);
 }
 
-bool EventHandler::handleGestureLongTap(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::handleGestureLongTap(const GestureEventWithHitTestResults& targetedEvent)
 {
 #if !OS(ANDROID)
     if (m_longTapShouldInvokeContextMenu) {
@@ -2309,7 +2362,7 @@ bool EventHandler::handleGestureLongTap(const GestureEventWithHitTestResults& ta
         return sendContextMenuEventForGesture(targetedEvent);
     }
 #endif
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
 bool EventHandler::handleScrollGestureOnResizer(Node* eventTarget, const PlatformGestureEvent& gestureEvent)
@@ -2339,25 +2392,22 @@ bool EventHandler::handleScrollGestureOnResizer(Node* eventTarget, const Platfor
     return false;
 }
 
-bool EventHandler::passScrollGestureEventToWidget(const PlatformGestureEvent& gestureEvent, LayoutObject* layoutObject)
+WebInputEventResult EventHandler::passScrollGestureEventToWidget(const PlatformGestureEvent& gestureEvent, LayoutObject* layoutObject)
 {
     ASSERT(gestureEvent.isScrollEvent());
 
-    if (!m_lastGestureScrollOverWidget)
-        return false;
-
-    if (!layoutObject || !layoutObject->isLayoutPart())
-        return false;
+    if (!m_lastGestureScrollOverWidget || !layoutObject || !layoutObject->isLayoutPart())
+        return WebInputEventResult::NotHandled;
 
     Widget* widget = toLayoutPart(layoutObject)->widget();
 
     if (!widget || !widget->isFrameView())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     return toFrameView(widget)->frame().eventHandler().handleGestureScrollEvent(gestureEvent);
 }
 
-bool EventHandler::handleGestureScrollEnd(const PlatformGestureEvent& gestureEvent)
+WebInputEventResult EventHandler::handleGestureScrollEnd(const PlatformGestureEvent& gestureEvent)
 {
     RefPtrWillBeRawPtr<Node> node = m_scrollGestureHandlingNode;
 
@@ -2372,18 +2422,18 @@ bool EventHandler::handleGestureScrollEnd(const PlatformGestureEvent& gestureEve
     }
 
     clearGestureScrollState();
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
-bool EventHandler::handleGestureScrollBegin(const PlatformGestureEvent& gestureEvent)
+WebInputEventResult EventHandler::handleGestureScrollBegin(const PlatformGestureEvent& gestureEvent)
 {
     Document* document = m_frame->document();
     if (!document->layoutView())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     FrameView* view = m_frame->view();
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     // If there's no layoutObject on the node, send the event to the nearest ancestor with a layoutObject.
     // Needed for <option> and <optgroup> elements so we can touch scroll <select>s
@@ -2394,7 +2444,7 @@ bool EventHandler::handleGestureScrollBegin(const PlatformGestureEvent& gestureE
         if (RuntimeEnabledFeatures::scrollCustomizationEnabled())
             m_scrollGestureHandlingNode = m_frame->document()->documentElement();
         else
-            return false;
+            return WebInputEventResult::NotHandled;
     }
     ASSERT(m_scrollGestureHandlingNode);
 
@@ -2409,7 +2459,7 @@ bool EventHandler::handleGestureScrollBegin(const PlatformGestureEvent& gestureE
         if (m_frame->isMainFrame())
             m_frame->host()->topControls().scrollBegin();
     }
-    return true;
+    return WebInputEventResult::HandledSystem;
 }
 
 void EventHandler::resetOverscroll(bool didScrollX, bool didScrollY)
@@ -2441,26 +2491,27 @@ void EventHandler::handleOverscroll(const ScrollResult& scrollResult, const Floa
     }
 }
 
-bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gestureEvent)
+WebInputEventResult EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gestureEvent)
 {
     ASSERT(gestureEvent.type() == PlatformEvent::GestureScrollUpdate);
 
     FloatSize delta(gestureEvent.deltaX(), gestureEvent.deltaY());
     if (delta.isZero())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     Node* node = m_scrollGestureHandlingNode.get();
     if (node) {
         LayoutObject* layoutObject = node->layoutObject();
         if (!layoutObject)
-            return false;
+            return WebInputEventResult::NotHandled;
 
         RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
 
         Node* stopNode = nullptr;
 
         // Try to send the event to the correct view.
-        if (passScrollGestureEventToWidget(gestureEvent, layoutObject)) {
+        WebInputEventResult result = passScrollGestureEventToWidget(gestureEvent, layoutObject);
+        if (result != WebInputEventResult::NotHandled) {
             if (gestureEvent.preventPropagation()
                 && !RuntimeEnabledFeatures::scrollCustomizationEnabled()) {
                 // This is an optimization which doesn't apply with
@@ -2470,7 +2521,7 @@ bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gesture
             // FIXME: we should allow simultaneous scrolling of nested
             // iframes along perpendicular axes. See crbug.com/466991.
             m_deltaConsumedForScrollSequence = true;
-            return true;
+            return result;
         }
 
         bool scrolled = false;
@@ -2515,12 +2566,12 @@ bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gesture
         }
         if (scrolled) {
             setFrameWasScrolledByUser();
-            return true;
+            return WebInputEventResult::HandledSystem;
         }
     }
 
     if (RuntimeEnabledFeatures::scrollCustomizationEnabled())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     // Try to scroll the frame view.
     ScrollResult scrollResult = m_frame->applyScrollDelta(delta, false);
@@ -2529,10 +2580,10 @@ bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gesture
     handleOverscroll(scrollResult, position, velocity);
     if (scrollResult.didScroll()) {
         setFrameWasScrolledByUser();
-        return true;
+        return WebInputEventResult::HandledSystem;
     }
 
-    return false;
+    return WebInputEventResult::NotHandled;
 }
 
 void EventHandler::clearGestureScrollState()
@@ -2870,11 +2921,11 @@ void EventHandler::applyTouchAdjustment(PlatformGestureEvent* gestureEvent, HitT
     }
 }
 
-bool EventHandler::sendContextMenuEvent(const PlatformMouseEvent& event, Node* overrideTargetNode)
+WebInputEventResult EventHandler::sendContextMenuEvent(const PlatformMouseEvent& event, Node* overrideTargetNode)
 {
     FrameView* v = m_frame->view();
     if (!v)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     // Clear mouse press state to avoid initiating a drag while context menu is up.
     m_mousePressed = false;
@@ -2888,15 +2939,15 @@ bool EventHandler::sendContextMenuEvent(const PlatformMouseEvent& event, Node* o
     return dispatchMouseEvent(EventTypeNames::contextmenu, targetNode, 0, event);
 }
 
-bool EventHandler::sendContextMenuEventForKey(Element* overrideTargetElement)
+WebInputEventResult EventHandler::sendContextMenuEventForKey(Element* overrideTargetElement)
 {
     FrameView* view = m_frame->view();
     if (!view)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     Document* doc = m_frame->document();
     if (!doc)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     // Clear mouse press state to avoid initiating a drag while context menu is up.
     m_mousePressed = false;
@@ -2960,7 +3011,7 @@ bool EventHandler::sendContextMenuEventForKey(Element* overrideTargetElement)
     return sendContextMenuEvent(mouseEvent, overrideTargetElement);
 }
 
-bool EventHandler::sendContextMenuEventForGesture(const GestureEventWithHitTestResults& targetedEvent)
+WebInputEventResult EventHandler::sendContextMenuEventForGesture(const GestureEventWithHitTestResults& targetedEvent)
 {
     const PlatformGestureEvent& gestureEvent = targetedEvent.event();
     unsigned modifiers = gestureEvent.modifiers();
@@ -3148,7 +3199,7 @@ bool EventHandler::handleAccessKey(const PlatformKeyboardEvent& evt)
     return true;
 }
 
-bool EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
+WebInputEventResult EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
 {
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
     m_frame->chromeClient().setToolTip(String(), LTR);
@@ -3163,7 +3214,7 @@ bool EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
             stopAutoscroll();
 
         // If we were in panscroll mode, we swallow the key event
-        return true;
+        return WebInputEventResult::HandledSuppressed;
     }
 #endif
 
@@ -3171,7 +3222,7 @@ bool EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
     // from pressing return in the location bar.
     RefPtrWillBeRawPtr<Node> node = eventTargetNodeForDocument(m_frame->document());
     if (!node)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     UserGestureIndicator gestureIndicator(DefinitelyProcessingUserGesture);
 
@@ -3185,8 +3236,12 @@ bool EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
         matchedAnAccessKey = handleAccessKey(initialKeyEvent);
 
     // FIXME: it would be fair to let an input method handle KeyUp events before DOM dispatch.
-    if (initialKeyEvent.type() == PlatformEvent::KeyUp || initialKeyEvent.type() == PlatformEvent::Char)
-        return !node->dispatchKeyEvent(initialKeyEvent);
+    if (initialKeyEvent.type() == PlatformEvent::KeyUp || initialKeyEvent.type() == PlatformEvent::Char) {
+        RefPtrWillBeRawPtr<KeyboardEvent> domEvent = KeyboardEvent::create(initialKeyEvent, m_frame->document()->domWindow());
+
+        bool dispatchResult = node->dispatchEvent(domEvent);
+        return eventToEventResult(domEvent, dispatchResult);
+    }
 
     PlatformKeyboardEvent keyDownEvent = initialKeyEvent;
     if (keyDownEvent.type() != PlatformEvent::RawKeyDown)
@@ -3197,36 +3252,36 @@ bool EventHandler::keyEvent(const PlatformKeyboardEvent& initialKeyEvent)
     keydown->setTarget(node);
 
     if (initialKeyEvent.type() == PlatformEvent::RawKeyDown) {
-        node->dispatchEvent(keydown);
+        if (!node->dispatchEvent(keydown))
+            return eventToEventResult(keydown, false);
         // If frame changed as a result of keydown dispatch, then return true to avoid sending a subsequent keypress message to the new frame.
         bool changedFocusedFrame = m_frame->page() && m_frame != m_frame->page()->focusController().focusedOrMainFrame();
-        return keydown->defaultHandled() || keydown->defaultPrevented() || changedFocusedFrame;
+        if (changedFocusedFrame)
+            return WebInputEventResult::HandledSystem;
+        return WebInputEventResult::NotHandled;
     }
 
-    node->dispatchEvent(keydown);
+    if (!node->dispatchEvent(keydown))
+        return eventToEventResult(keydown, false);
     // If frame changed as a result of keydown dispatch, then return early to avoid sending a subsequent keypress message to the new frame.
     bool changedFocusedFrame = m_frame->page() && m_frame != m_frame->page()->focusController().focusedOrMainFrame();
-    bool keydownResult = keydown->defaultHandled() || keydown->defaultPrevented() || changedFocusedFrame;
-    if (keydownResult)
-        return keydownResult;
+    if (changedFocusedFrame)
+        return WebInputEventResult::HandledSystem;
 
     // Focus may have changed during keydown handling, so refetch node.
     // But if we are dispatching a fake backward compatibility keypress, then we pretend that the keypress happened on the original node.
     node = eventTargetNodeForDocument(m_frame->document());
     if (!node)
-        return false;
+        return WebInputEventResult::NotHandled;
 
     PlatformKeyboardEvent keyPressEvent = initialKeyEvent;
     keyPressEvent.disambiguateKeyDownEvent(PlatformEvent::Char);
     if (keyPressEvent.text().isEmpty())
-        return keydownResult;
+        return WebInputEventResult::NotHandled;
     RefPtrWillBeRawPtr<KeyboardEvent> keypress = KeyboardEvent::create(keyPressEvent, m_frame->document()->domWindow());
     keypress->setTarget(node);
-    if (keydownResult)
-        keypress->setDefaultPrevented(true);
-    node->dispatchEvent(keypress);
-
-    return keydownResult || keypress->defaultPrevented() || keypress->defaultHandled();
+    bool dispatchResult = node->dispatchEvent(keypress);
+    return eventToEventResult(keypress, dispatchResult);
 }
 
 static WebFocusType focusDirectionForKey(const AtomicString& keyIdentifier)
@@ -3344,7 +3399,7 @@ void EventHandler::updateDragStateAfterEditDragIfNeeded(Element* rootEditableEle
 }
 
 // returns if we should continue "default processing", i.e., whether eventhandler canceled
-bool EventHandler::dispatchDragSrcEvent(const AtomicString& eventType, const PlatformMouseEvent& event)
+WebInputEventResult EventHandler::dispatchDragSrcEvent(const AtomicString& eventType, const PlatformMouseEvent& event)
 {
     return dispatchDragEvent(eventType, dragState().m_dragSrc.get(), event, dragState().m_dragDataTransfer.get());
 }
@@ -3433,7 +3488,7 @@ bool EventHandler::tryStartDrag(const MouseEventWithHitTestResults& event)
     // reset. Hence, need to check if this particular drag operation can
     // continue even if dispatchEvent() indicates no (direct) cancellation.
     // Do that by checking if m_dragSrc is still set.
-    m_mouseDownMayStartDrag = !dispatchDragSrcEvent(EventTypeNames::dragstart, m_mouseDown)
+    m_mouseDownMayStartDrag = dispatchDragSrcEvent(EventTypeNames::dragstart, m_mouseDown) == WebInputEventResult::NotHandled
         && !m_frame->selection().isInPasswordField() && dragState().m_dragSrc;
 
     // Invalidate clipboard here against anymore pasteboard writing for security. The drag
@@ -3734,7 +3789,7 @@ public:
 
 } // namespace
 
-bool EventHandler::dispatchTouchEvents(const PlatformTouchEvent& event,
+WebInputEventResult EventHandler::dispatchTouchEvents(const PlatformTouchEvent& event,
     WillBeHeapVector<TouchInfo>& touchInfos, bool freshTouchEvents, bool allTouchReleased)
 {
     // Build up the lists to use for the 'touches', 'targetTouches' and
@@ -3806,7 +3861,7 @@ bool EventHandler::dispatchTouchEvents(const PlatformTouchEvent& event,
         m_touchSequenceUserGestureToken.clear();
     }
 
-    bool swallowedEvent = false;
+    WebInputEventResult eventResult = WebInputEventResult::NotHandled;
 
     // Now iterate through the changedTouches list and m_targets within it, sending
     // TouchEvents to the targets as required.
@@ -3822,15 +3877,15 @@ bool EventHandler::dispatchTouchEvents(const PlatformTouchEvent& event,
                 eventName, touchEventTarget->toNode()->document().domWindow(),
                 event.modifiers(), event.cancelable(), event.causesScrollingIfUncanceled(), event.timestamp());
 
-            touchEventTarget->dispatchEvent(touchEvent.get());
-            swallowedEvent = swallowedEvent || touchEvent->defaultPrevented() || touchEvent->defaultHandled();
+            bool dispatchResult = touchEventTarget->dispatchEvent(touchEvent.get());
+            eventResult = mergeEventResult(eventResult, eventToEventResult(touchEvent, dispatchResult));
         }
     }
 
-    return swallowedEvent;
+    return eventResult;
 }
 
-bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
+WebInputEventResult EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleTouchEvent");
 
@@ -3869,7 +3924,7 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
     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 false;
+        return WebInputEventResult::NotHandled;
     }
 
     // First do hit tests for any new touch points.
@@ -3932,7 +3987,7 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
             m_touchSequenceDocument.clear();
             m_touchSequenceUserGestureToken.clear();
         }
-        return false;
+        return WebInputEventResult::NotHandled;
     }
 
     // Compute and store the common info used by both PointerEvent and TouchEvent.
@@ -4011,13 +4066,13 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
     // 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).
 
-    bool swallowedTouchEvent = dispatchTouchEvents(event, touchInfos, freshTouchEvents,
+    WebInputEventResult eventResult = dispatchTouchEvents(event, touchInfos, freshTouchEvents,
         allTouchReleased);
 
     if (!m_inPointerCanceledState) {
         // Check if we need to stop firing pointer events because of a touch action.
         // See: www.w3.org/TR/pointerevents/#declaring-candidate-regions-for-default-touch-behaviors
-        if (event.causesScrollingIfUncanceled() && !swallowedTouchEvent) {
+        if (event.causesScrollingIfUncanceled() && eventResult == WebInputEventResult::NotHandled) {
             m_inPointerCanceledState = true;
             sendPointerCancels(touchInfos);
         }
@@ -4025,7 +4080,7 @@ bool EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
         m_inPointerCanceledState = false;
     }
 
-    return swallowedTouchEvent;
+    return eventResult;
 }
 
 void EventHandler::setLastKnownMousePosition(const PlatformMouseEvent& event)
@@ -4041,33 +4096,39 @@ void EventHandler::conditionallyEnableMouseEventForPointerTypeMouse(const Platfo
         m_preventMouseEventForPointerTypeMouse = false;
 }
 
-bool EventHandler::passMousePressEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
+WebInputEventResult EventHandler::passMousePressEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
 {
     selectionController().passMousePressEventToSubframe(mev);
-    subframe->eventHandler().handleMousePressEvent(mev.event());
-    return true;
+    WebInputEventResult result = subframe->eventHandler().handleMousePressEvent(mev.event());
+    if (result != WebInputEventResult::NotHandled)
+        return result;
+    return WebInputEventResult::HandledSystem;
 }
 
-bool EventHandler::passMouseMoveEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe, HitTestResult* hoveredNode)
+WebInputEventResult EventHandler::passMouseMoveEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe, HitTestResult* hoveredNode)
 {
     if (m_mouseDownMayStartDrag)
-        return false;
-    subframe->eventHandler().handleMouseMoveOrLeaveEvent(mev.event(), hoveredNode);
-    return true;
+        return WebInputEventResult::NotHandled;
+    WebInputEventResult result = subframe->eventHandler().handleMouseMoveOrLeaveEvent(mev.event(), hoveredNode);
+    if (result != WebInputEventResult::NotHandled)
+        return result;
+    return WebInputEventResult::HandledSystem;
 }
 
-bool EventHandler::passMouseReleaseEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
+WebInputEventResult EventHandler::passMouseReleaseEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
 {
-    subframe->eventHandler().handleMouseReleaseEvent(mev.event());
-    return true;
+    WebInputEventResult result = subframe->eventHandler().handleMouseReleaseEvent(mev.event());
+    if (result != WebInputEventResult::NotHandled)
+        return result;
+    return WebInputEventResult::HandledSystem;
 }
 
-bool EventHandler::passWheelEventToWidget(const PlatformWheelEvent& wheelEvent, Widget& widget)
+WebInputEventResult EventHandler::passWheelEventToWidget(const PlatformWheelEvent& wheelEvent, Widget& widget)
 {
     // If not a FrameView, then probably a plugin widget.  Those will receive
     // the event via an EventTargetNode dispatch when this returns false.
     if (!widget.isFrameView())
-        return false;
+        return WebInputEventResult::NotHandled;
 
     return toFrameView(&widget)->frame().eventHandler().handleWheelEvent(wheelEvent);
 }