Implement a Hit Test Cache.

Source/core/layout/LayoutTable.cpp

Index: Source/core/layout/LayoutTable.cpp
diff --git a/Source/core/layout/LayoutTable.cpp b/Source/core/layout/LayoutTable.cpp
index 4e65058dfcedb3385814390ee097275077377c49..8b5207b7a788039bca43e5fa2d2080e3fcc828ea 100644
--- a/Source/core/layout/LayoutTable.cpp
+++ b/Source/core/layout/LayoutTable.cpp
@@ -1340,7 +1340,8 @@ bool LayoutTable::nodeAtPoint(HitTestResult& result, const HitTestLocation& loca
             if (child->isBox() && !toLayoutBox(child)->hasSelfPaintingLayer() && (child->isTableSection() || child->isTableCaption())) {
                 LayoutPoint childPoint = flipForWritingModeForChild(toLayoutBox(child), adjustedLocation);
                 if (child->nodeAtPoint(result, locationInContainer, childPoint, action)) {
-                    updateHitTestResult(result, toLayoutPoint(locationInContainer.point() - childPoint));
+                    // TODO(dtapuska): Calculate child's rect
+                    updateHitTestResult(result, toLayoutPoint(locationInContainer.point() - childPoint), result.validityRect());
                     return true;
                 }
             }
@@ -1350,11 +1351,11 @@ bool LayoutTable::nodeAtPoint(HitTestResult& result, const HitTestLocation& loca
     // Check our bounds next.
     LayoutRect boundsRect(adjustedLocation, size());
     if (visibleToHitTestRequest(result.hitTestRequest()) && (action == HitTestBlockBackground || action == HitTestChildBlockBackground) && locationInContainer.intersects(boundsRect)) {
-        updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - toLayoutSize(adjustedLocation)));
+        updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - toLayoutSize(adjustedLocation)), boundsRect);
         if (!result.addNodeToListBasedTestResult(node(), locationInContainer, boundsRect))
             return true;
     }
-
+    result.shrinkValidityRect(boundsRect);
     return false;
 }