Implement elementsFromPoint

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 2da13ecbec963d691a431cbbcd55ad5c41b5b19f..3f78d51f18db61b32c3ffcc91a0bf2f04d572ed6 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -864,6 +864,8 @@ HitTestResult EventHandler::hitTestResultAtPoint(const LayoutPoint& point, HitTe
 {
     TRACE_EVENT0("blink", "EventHandler::hitTestResultAtPoint");
 
+    ASSERT((hitType & HitTestRequest::ListBased) || padding.isEmpty());
+
     // We always send hitTestResultAtPoint to the main frame if we have one,
     // otherwise we might hit areas that are obscured by higher frames.
     if (m_frame->page()) {
@@ -2591,7 +2593,7 @@ bool EventHandler::bestClickableNodeForHitTestResult(const HitTestResult& result
     IntRect touchRect = m_frame->view()->contentsToWindow(result.hitTestLocation().boundingBox());
 
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestClickableCandidate(targetNode, targetPoint, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>> (nodes));
@@ -2603,7 +2605,7 @@ bool EventHandler::bestContextMenuNodeForHitTestResult(const HitTestResult& resu
     IntPoint touchCenter = m_frame->view()->contentsToWindow(result.roundedPointInMainFrame());
     IntRect touchRect = m_frame->view()->contentsToWindow(result.hitTestLocation().boundingBox());
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestContextMenuCandidate(targetNode, targetPoint, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>>(nodes));
@@ -2612,11 +2614,16 @@ bool EventHandler::bestContextMenuNodeForHitTestResult(const HitTestResult& resu
 bool EventHandler::bestZoomableAreaForTouchPoint(const IntPoint& touchCenter, const IntSize& touchRadius, IntRect& targetArea, Node*& targetNode)
 {
     IntPoint hitTestPoint = m_frame->view()->windowToContents(touchCenter);
-    HitTestResult result = hitTestResultAtPoint(hitTestPoint, HitTestRequest::ReadOnly | HitTestRequest::Active, LayoutSize(touchRadius));
+
+    HitTestRequest::HitTestRequestType hitType = HitTestRequest::ReadOnly | HitTestRequest::Active;
+    if (!touchRadius.isEmpty())
+        hitType |= HitTestRequest::ListBased;

[Rick Byers, 2015/02/20 20:02:24]

This function it intended to be used only with a non-empty radius (seems weird
to add logic that results in working on an empty list when radius is 0). 
Perhaps just bail out early on zero radius?  We could assert non-zero except I
believe clusterFuzz will fuzz calls to window.internals APIs (at least I know it
fuzzes calls to eventSender).

[pdr., 2015/02/22 23:28:13]

Done

+
+    HitTestResult result = hitTestResultAtPoint(hitTestPoint, hitType, LayoutSize(touchRadius));
 
     IntRect touchRect(touchCenter - touchRadius, touchRadius + touchRadius);
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestZoomableArea(targetNode, targetArea, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>>(nodes));
@@ -2670,7 +2677,10 @@ GestureEventWithHitTestResults EventHandler::hitTestResultForGestureEvent(const
     LayoutSize padding;
     if (shouldApplyTouchAdjustment(gestureEvent)) {
         padding = LayoutSize(gestureEvent.area());
-        padding.scale(1.f / 2);
+        if (!padding.isEmpty()) {
+            padding.scale(1.f / 2);
+            hitType |= HitTestRequest::ListBased;
+        }
     }
     HitTestResult hitTestResult = hitTestResultAtPoint(hitTestPoint, hitType | HitTestRequest::ReadOnly, padding);
 
@@ -2687,7 +2697,7 @@ GestureEventWithHitTestResults EventHandler::hitTestResultForGestureEvent(const
         LocalFrame* hitFrame = hitTestResult.innerNodeFrame();
         if (!hitFrame)
             hitFrame = m_frame;
-        hitTestResult = hitTestResultInFrame(hitFrame, hitFrame->view()->windowToContents(adjustedEvent.position()), hitType | HitTestRequest::ReadOnly);
+        hitTestResult = hitTestResultInFrame(hitFrame, hitFrame->view()->windowToContents(adjustedEvent.position()), (hitType | HitTestRequest::ReadOnly) & ~HitTestRequest::ListBased);
     }
 
     // If we did a rect-based hit test it must be resolved to the best single node by now to