Untangle multicol coordinate space conversion from offsetFromContainer().

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 c4c3c731219ce47c468dfbc87b2f6647a999c561..f8faa13f535090fed7cf2c623eafda29140277cf 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
@@ -865,8 +865,14 @@ const LayoutObject* LayoutBoxModelObject::pushMappingToContainer(const LayoutBox
         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;