*** NOT FOR LANDING *** mapLocalToContainer and offsetFromContainer cleanup.

Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 831 matching lines @@
         break;
     }
     x = std::min(x, std::max<LayoutUnit>(maxX - caretWidth(), 0));
 
     LayoutUnit height = style()->fontMetrics().height();
     LayoutUnit verticalSpace = lineHeight(true, currentStyle.isHorizontalWritingMode() ? HorizontalLine : VerticalLine,  PositionOfInteriorLineBoxes) - height;
     LayoutUnit y = paddingTop() + borderTop() + (verticalSpace / 2);
     return currentStyle.isHorizontalWritingMode() ? LayoutRect(x, y, caretWidth(), height) : LayoutRect(y, x, height, caretWidth());
 }
 
+LayoutSize LayoutBoxModelObject::offsetFromContainer(const LayoutObject* o) const
+{
+    LayoutSize offset;
+    if (isRelPositioned())
+        offset += offsetForInFlowPosition();
+    return offset + LayoutObject::offsetFromContainer(o);
+}
+
 void LayoutBoxModelObject::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
 {
     LayoutObject* o = container();
     if (!o)
         return;
 
     o->mapAbsoluteToLocalPoint(mode, transformState);
 
-    LayoutSize containerOffset = offsetFromContainer(o, LayoutPoint());
-
-    if (o->isLayoutFlowThread()) {
-        // Descending into a flow thread. Convert to the local coordinate space, i.e. flow thread coordinates.
-        const LayoutFlowThread* flowThread = toLayoutFlowThread(o);
-        LayoutPoint visualPoint = LayoutPoint(transformState.mappedPoint());
-        transformState.move(visualPoint - flowThread->visualPointToFlowThreadPoint(visualPoint));
-        // |containerOffset| is also in visual coordinates. Convert to flow thread coordinates.
-        // TODO(mstensho): Wouldn't it be better add a parameter to instruct offsetFromContainer()
-        // to return flowthread coordinates in the first place? We're effectively performing two
-        // conversions here, when in fact none is needed.
-        containerOffset = toLayoutSize(flowThread->visualPointToFlowThreadPoint(toLayoutPoint(containerOffset)));
-    }
-
+    LayoutSize containerOffset = offsetFromContainer(o);
     bool preserve3D = mode & UseTransforms && (o->style()->preserves3D() || style()->preserves3D());
     if (mode & UseTransforms && shouldUseTransformFromContainer(o)) {
         TransformationMatrix t;
         getTransformFromContainer(o, containerOffset, t);
         transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
     } else {
         transformState.move(containerOffset.width(), containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
     }
 }
 
@@ skipping 10 matching lines @@
     bool isFixedPos = !isInline && style()->position() == FixedPosition;
     bool hasTransform = !isInline && hasLayer() && layer()->transform();
 
     LayoutSize adjustmentForSkippedAncestor;
     if (ancestorSkipped) {
         // There can't be a transform between paintInvalidationContainer and ancestorToStopAt, because transforms create containers, so it should be safe
         // to just subtract the delta between the ancestor and ancestorToStopAt.
         adjustmentForSkippedAncestor = -ancestorToStopAt->offsetFromAncestorContainer(container);
     }
 
-    bool offsetDependsOnPoint = false;
-    LayoutSize containerOffset = offsetFromContainer(container, LayoutPoint(), &offsetDependsOnPoint);
+    bool offsetDependsOnPoint = container->isBox() && (container->style()->isFlippedBlocksWritingMode() || container->isLayoutFlowThread());
+    LayoutSize containerOffset = offsetFromContainer(container);
+    containerOffset += container->columnOffset(toLayoutPoint(containerOffset));
 
     bool preserve3D = container->style()->preserves3D() || style()->preserves3D();
     if (shouldUseTransformFromContainer(container)) {
         TransformationMatrix t;
         getTransformFromContainer(container, containerOffset, t);
         t.translateRight(adjustmentForSkippedAncestor.width().toFloat(), adjustmentForSkippedAncestor.height().toFloat());
         geometryMap.push(this, t, preserve3D, offsetDependsOnPoint, isFixedPos, hasTransform);
     } else {
         containerOffset += adjustmentForSkippedAncestor;
         geometryMap.push(this, containerOffset, preserve3D, offsetDependsOnPoint, isFixedPos, hasTransform);
@@ skipping 57 matching lines @@
     if (rootElementStyle->hasBackground())
         return false;
 
     if (node() != document().firstBodyElement())
         return false;
 
     return true;
 }
 
 } // namespace blink