Don't allow column spanners inside transforms.

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

 /*
  * Copyright (C) 2012 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 69 matching lines @@
         return false;
     return toLayoutBlockFlow(object).multiColumnFlowThread();
 }
 
 static inline bool canContainSpannerInParentFragmentationContext(const LayoutObject& object)
 {
     if (!object.isLayoutBlockFlow())
         return false;
     const LayoutBlockFlow& blockFlow = toLayoutBlockFlow(object);
     return !blockFlow.createsNewFormattingContext()
+        && !blockFlow.hasTransformRelatedProperty()

[eae, 2016/04/22 16:52:23]

Could you please add a comment to this method that explains the logic? Something
like the CL description would be great.

[mstensho (USE GERRIT), 2016/04/22 17:44:39]

Done.

         && blockFlow.getPaginationBreakability() != LayoutBox::ForbidBreaks
         && !isMultiColumnContainer(blockFlow);
 }
 
 static inline bool hasAnyColumnSpanners(const LayoutMultiColumnFlowThread& flowThread)
 {
     LayoutBox* firstBox = flowThread.firstMultiColumnBox();
     return firstBox && (firstBox != flowThread.lastMultiColumnBox() || firstBox->isLayoutMultiColumnSpannerPlaceholder());
 }
 
@@ skipping 929 matching lines @@
         }
         if (canContainSpannerInParentFragmentationContext(*object))
             next = object->nextInPreOrder(&root);
         else
             next = object->nextInPreOrderAfterChildren(&root);
     }
     return true;
 }
 
 } // namespace blink