Implement elementsFromPoint

Source/core/rendering/RenderView.cpp

Index: Source/core/rendering/RenderView.cpp
diff --git a/Source/core/rendering/RenderView.cpp b/Source/core/rendering/RenderView.cpp
index 8e54ecd752911d3713468f519b22b758e9d8cf5f..0ecc5189af8ddfc083c915581c954a1a6848ae93 100644
--- a/Source/core/rendering/RenderView.cpp
+++ b/Source/core/rendering/RenderView.cpp
@@ -88,6 +88,8 @@ bool RenderView::hitTest(const HitTestRequest& request, const HitTestLocation& l
     TRACE_EVENT0("blink", "RenderView::hitTest");
     m_hitTestCount++;
 
+    ASSERT(!location.isRectBasedTest() || request.listBased());
+
     // We have to recursively update layout/style here because otherwise, when the hit test recurses
     // into a child document, it could trigger a layout on the parent document, which can destroy Layers
     // that are higher up in the call stack, leading to crashes.