Untangle multicol coordinate space conversion from offsetFromContainer().

third_party/WebKit/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 847 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);
+    LayoutSize containerOffset = offsetFromContainer(container);
+    bool offsetDependsOnPoint;
+    if (container->isLayoutFlowThread()) {
+        containerOffset += container->columnOffset(toLayoutPoint(containerOffset));
+        offsetDependsOnPoint = true;
+    } else {
+        offsetDependsOnPoint = container->style()->isFlippedBlocksWritingMode() && container->isBox();
+    }
 
     bool preserve3D = container->style()->preserves3D() || style()->preserves3D();
     GeometryInfoFlags flags = 0;
     if (preserve3D)
         flags |= AccumulatingTransform;
     if (offsetDependsOnPoint)
         flags |= IsNonUniform;
     if (isFixedPos)
         flags |= IsFixedPosition;
     if (hasTransform)
@@ skipping 80 matching lines @@
     if (rootElementStyle->hasBackground())
         return false;
 
     if (node() != document().firstBodyElement())
         return false;
 
     return true;
 }
 
 } // namespace blink