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

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
index a1dcdcd8fffcd632b494b647bf4e8eb9477420cc..70a2bc553edd783dc572a7af7e93e5d0743fc4ec 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
@@ -768,7 +768,7 @@ LayoutSize LayoutBoxModelObject::stickyPositionOffset() const
     return LayoutSize(scrollableArea->stickyConstraintsMap().get(layer()).computeStickyOffset(constrainingRect));
 }
 
-LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeTo(const LayoutPoint& startPoint, const Element* element) const
+LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeToOffsetParent(const LayoutPoint& startPoint) const
 {
     // If the element is the HTML body element or doesn't have a parent
     // return 0 and stop this algorithm.
@@ -778,8 +778,10 @@ LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeTo(const LayoutPoint&
     LayoutPoint referencePoint = startPoint;
     referencePoint.move(parent()->columnOffset(referencePoint));
 
-    // If the base element is null, return the distance between the canvas origin and
-    // the left border edge of the element and stop this algorithm.
+    // If the offsetParent of the element is null, or is the HTML body element,
+    // return the distance between the canvas origin and the left border edge
+    // of the element and stop this algorithm.
+    Element* element = offsetParent();
     if (!element)
         return referencePoint;
 
@@ -819,28 +821,28 @@ LayoutSize LayoutBoxModelObject::offsetForInFlowPosition() const
     return LayoutSize();
 }
 
-LayoutUnit LayoutBoxModelObject::offsetLeft(const Element* parent) const
+LayoutUnit LayoutBoxModelObject::offsetLeft() const
 {
     // Note that LayoutInline and LayoutBox override this to pass a different
-    // startPoint to adjustedPositionRelativeTo.
-    return adjustedPositionRelativeTo(LayoutPoint(), parent).x();
+    // startPoint to adjustedPositionRelativeToOffsetParent.
+    return adjustedPositionRelativeToOffsetParent(LayoutPoint()).x();
 }
 
-LayoutUnit LayoutBoxModelObject::offsetTop(const Element* parent) const
+LayoutUnit LayoutBoxModelObject::offsetTop() const
 {
     // Note that LayoutInline and LayoutBox override this to pass a different
-    // startPoint to adjustedPositionRelativeTo.
-    return adjustedPositionRelativeTo(LayoutPoint(), parent).y();
+    // startPoint to adjustedPositionRelativeToOffsetParent.
+    return adjustedPositionRelativeToOffsetParent(LayoutPoint()).y();
 }
 
-int LayoutBoxModelObject::pixelSnappedOffsetWidth(const Element* parent) const
+int LayoutBoxModelObject::pixelSnappedOffsetWidth() const
 {
-    return snapSizeToPixel(offsetWidth(), offsetLeft(parent));
+    return snapSizeToPixel(offsetWidth(), offsetLeft());
 }
 
-int LayoutBoxModelObject::pixelSnappedOffsetHeight(const Element* parent) const
+int LayoutBoxModelObject::pixelSnappedOffsetHeight() const
 {
-    return snapSizeToPixel(offsetHeight(), offsetTop(parent));
+    return snapSizeToPixel(offsetHeight(), offsetTop());
 }
 
 LayoutUnit LayoutBoxModelObject::computedCSSPadding(const Length& padding) const