Do not commit: Revert of r404081 and r402757 for perf testing purposes.

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index ef260adf32dc31fb8e8c0d0dfbfbde675c104369..0bcf77243892135e22812a8b23726200945e0f96 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -622,13 +622,13 @@ void Element::callApplyScroll(ScrollState& scrollState)
         nativeApplyScroll(scrollState);
     if (callback->nativeScrollBehavior() == WebNativeScrollBehavior::PerformAfterNativeScroll)
         callback->handleEvent(&scrollState);
-}
+};
 
 int Element::offsetLeft()
 {
     document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
     if (LayoutBoxModelObject* layoutObject = layoutBoxModelObject())
-        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetLeft(offsetParent())), layoutObject->styleRef()).round();
+        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetLeft()), layoutObject->styleRef()).round();
     return 0;
 }
 
@@ -636,7 +636,7 @@ int Element::offsetTop()
 {
     document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
     if (LayoutBoxModelObject* layoutObject = layoutBoxModelObject())
-        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetTop(offsetParent())), layoutObject->styleRef()).round();
+        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetTop()), layoutObject->styleRef()).round();
     return 0;
 }
 
@@ -644,7 +644,7 @@ int Element::offsetWidth()
 {
     document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
     if (LayoutBoxModelObject* layoutObject = layoutBoxModelObject())
-        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetWidth(offsetParent())), layoutObject->styleRef()).round();
+        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetWidth()), layoutObject->styleRef()).round();
     return 0;
 }
 
@@ -652,7 +652,7 @@ int Element::offsetHeight()
 {
     document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
     if (LayoutBoxModelObject* layoutObject = layoutBoxModelObject())
-        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetHeight(offsetParent())), layoutObject->styleRef()).round();
+        return adjustLayoutUnitForAbsoluteZoom(LayoutUnit(layoutObject->pixelSnappedOffsetHeight()), layoutObject->styleRef()).round();
     return 0;
 }
 
@@ -661,7 +661,17 @@ Element* Element::offsetParent()
     document().updateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
 
     LayoutObject* layoutObject = this->layoutObject();
-    return layoutObject ? layoutObject->offsetParent() : nullptr;
+    if (!layoutObject)
+        return nullptr;
+
+    Element* element = layoutObject->offsetParent();
+    if (!element)
+        return nullptr;
+
+    if (element->isInShadowTree() && !element->containingShadowRoot()->isOpenOrV0())
+        return nullptr;
+
+    return element;
 }
 
 int Element::clientLeft()