Re-add extra hit-tests on GestureTap

Source/core/page/EventHandler.cpp

Index: Source/core/page/EventHandler.cpp
diff --git a/Source/core/page/EventHandler.cpp b/Source/core/page/EventHandler.cpp
index e409f3085feaaca36392fe9bb84bb853e1c0efe1..90556386e5ed474eb962c52a44500080274eb5bd 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -2227,29 +2227,51 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
 
     // We use the adjusted position so the application isn't surprised to see a event with
     // co-ordinates outside the target's bounds.
-    IntPoint adjustedPoint = gestureEvent.position();
+    IntPoint adjustedPoint = m_frame->view()->windowToContents(gestureEvent.position());
+
+    // Do a new hit-test at the (adjusted) gesture co-ordinates. This is necessary because
+    // touch adjustment sometimes returns a different node than what hit testing would return
+    // for the same point.
+    // FIXME: Fix touch adjustment to avoid the need for a redundant hit test. http://crbug.com/398914
+    HitTestResult newHitTest = hitTestResultInFrame(m_frame, adjustedPoint, HitTestRequest::ReadOnly);
 
     PlatformMouseEvent fakeMouseMove(adjustedPoint, gestureEvent.globalPosition(),
         NoButton, PlatformEvent::MouseMoved, /* clickCount */ 0,
         modifiers, PlatformMouseEvent::FromTouch, gestureEvent.timestamp());
-    dispatchMouseEvent(EventTypeNames::mousemove, targetedEvent.targetNode(), 0, fakeMouseMove, true);
+    dispatchMouseEvent(EventTypeNames::mousemove, newHitTest.targetNode(), 0, fakeMouseMove, true);
+
+    // Do a new hit-test in case the mousemove event changed the DOM.
+    // FIXME: Use a hit-test cache to avoid unnecessary hit tests. http://crbug.com/398920
+    newHitTest = hitTestResultInFrame(m_frame, adjustedPoint, HitTestRequest::ReadOnly);
+    m_clickNode = newHitTest.targetNode();
+    if (m_clickNode && m_clickNode->isTextNode())
+        m_clickNode = NodeRenderingTraversal::parent(m_clickNode.get());
 
     PlatformMouseEvent fakeMouseDown(adjustedPoint, gestureEvent.globalPosition(),
         LeftButton, PlatformEvent::MousePressed, gestureEvent.tapCount(),
         modifiers, PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
-    bool swallowMouseDownEvent = !dispatchMouseEvent(EventTypeNames::mousedown, targetedEvent.targetNode(), gestureEvent.tapCount(), fakeMouseDown, true);
+    bool swallowMouseDownEvent = !dispatchMouseEvent(EventTypeNames::mousedown, newHitTest.targetNode(), gestureEvent.tapCount(), fakeMouseDown, true);
     if (!swallowMouseDownEvent)
         swallowMouseDownEvent = handleMouseFocus(fakeMouseDown);
     if (!swallowMouseDownEvent)
-        swallowMouseDownEvent = handleMousePressEvent(MouseEventWithHitTestResults(fakeMouseDown, targetedEvent.hitTestResult()));
+        swallowMouseDownEvent = handleMousePressEvent(MouseEventWithHitTestResults(fakeMouseDown, newHitTest));
 
+    // FIXME: Use a hit-test cache to avoid unnecessary hit tests. http://crbug.com/398920
+    newHitTest = hitTestResultInFrame(m_frame, adjustedPoint, HitTestRequest::ReadOnly);
     PlatformMouseEvent fakeMouseUp(adjustedPoint, gestureEvent.globalPosition(),
         LeftButton, PlatformEvent::MouseReleased, gestureEvent.tapCount(),
         modifiers, PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
-    bool swallowMouseUpEvent = !dispatchMouseEvent(EventTypeNames::mouseup, targetedEvent.targetNode(), gestureEvent.tapCount(), fakeMouseUp, false);
-    bool swallowClickEvent = !dispatchMouseEvent(EventTypeNames::click, targetedEvent.targetNode(), gestureEvent.tapCount(), fakeMouseUp, true);
+    bool swallowMouseUpEvent = !dispatchMouseEvent(EventTypeNames::mouseup, newHitTest.targetNode(), gestureEvent.tapCount(), fakeMouseUp, false);
+
+    bool swallowClickEvent = false;
+    if (m_clickNode) {
+        Node* clickTargetNode = newHitTest.targetNode()->commonAncestor(*m_clickNode, parentForClickEvent);
+        swallowClickEvent = !dispatchMouseEvent(EventTypeNames::click, clickTargetNode, gestureEvent.tapCount(), fakeMouseUp, true);
+        m_clickNode = nullptr;
+    }
+
     if (!swallowMouseUpEvent)
-        swallowMouseUpEvent = handleMouseReleaseEvent(MouseEventWithHitTestResults(fakeMouseUp, targetedEvent.hitTestResult()));
+        swallowMouseUpEvent = handleMouseReleaseEvent(MouseEventWithHitTestResults(fakeMouseUp, newHitTest));
 
     return swallowMouseDownEvent | swallowMouseUpEvent | swallowClickEvent;
 }