[New Multicolumn] balancer confused by content with top margins.

Source/core/rendering/LayoutState.cpp

 /*
  * Copyright (C) 2007 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 71 matching lines @@
     }
 
     // If we establish a new page height, then cache the offset to the top of the first page.
     // We can compare this later on to figure out what part of the page we're actually on,
     if (pageLogicalHeight || m_columnInfo || renderer.isRenderFlowThread()) {
         m_pageLogicalHeight = pageLogicalHeight;
         bool isFlipped = renderer.style()->isFlippedBlocksWritingMode();
         m_pageOffset = LayoutSize(m_layoutOffset.width() + (!isFlipped ? renderer.borderLeft() + renderer.paddingLeft() : renderer.borderRight() + renderer.paddingRight()),
             m_layoutOffset.height() + (!isFlipped ? renderer.borderTop() + renderer.paddingTop() : renderer.borderBottom() + renderer.paddingBottom()));
         m_pageLogicalHeightChanged = pageLogicalHeightChanged;
+        m_isPaginated = true;
     } else {
         // If we don't establish a new page height, then propagate the old page height and offset down.
         m_pageLogicalHeight = m_next->m_pageLogicalHeight;
         m_pageLogicalHeightChanged = m_next->m_pageLogicalHeightChanged;
         m_pageOffset = m_next->m_pageOffset;
 
         // Disable pagination for objects we don't support. For now this includes overflow:scroll/auto, inline blocks and
         // writing mode roots.
-        if (renderer.isUnsplittableForPagination())
+        if (renderer.isUnsplittableForPagination()) {
             m_pageLogicalHeight = 0;
+            m_isPaginated = false;
+        } else {
+            m_isPaginated = m_pageLogicalHeight || m_next->m_columnInfo || renderer.flowThreadContainingBlock();
+        }
     }
 
     if (!m_columnInfo)
         m_columnInfo = m_next->m_columnInfo;
 
     if (renderer.isRenderBlock()) {
         const RenderBlock& renderBlock = toRenderBlock(renderer);
         m_shapeInsideInfo = renderBlock.shapeInsideInfo();
         if (!m_shapeInsideInfo && m_next->m_shapeInsideInfo && renderBlock.allowsShapeInsideInfoSharing(&m_next->m_shapeInsideInfo->owner()))
             m_shapeInsideInfo = m_next->m_shapeInsideInfo;
     }
 
     if (!RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
         m_layoutDelta = m_next->m_layoutDelta;
 #if !ASSERT_DISABLED
         m_layoutDeltaXSaturated = m_next->m_layoutDeltaXSaturated;
         m_layoutDeltaYSaturated = m_next->m_layoutDeltaYSaturated;
 #endif
     }
 
-    m_isPaginated = m_pageLogicalHeight || m_columnInfo || renderer.isRenderFlowThread();
-
     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
 }
 
 LayoutState::LayoutState(RenderObject& root)
     : m_clipped(false)
     , m_isPaginated(false)
     , m_pageLogicalHeightChanged(false)
 #if !ASSERT_DISABLED
     , m_layoutDeltaXSaturated(false)
     , m_layoutDeltaYSaturated(false)
@@ skipping 43 matching lines @@
 }
 
 void LayoutState::addForcedColumnBreak(const RenderBox& child, const LayoutUnit& childLogicalOffset)
 {
     if (!m_columnInfo || m_columnInfo->columnHeight())
         return;
     m_columnInfo->addForcedBreak(pageLogicalOffset(child, childLogicalOffset));
 }
 
 } // namespace WebCore