Jump to the next outer column when an inner column is too short.

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

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 145 matching lines @@
 
 void LayoutFlowThread::generateColumnSetIntervalTree()
 {
     // FIXME: Optimize not to clear the interval all the time. This implies manually managing the tree nodes lifecycle.
     m_multiColumnSetIntervalTree.clear();
     m_multiColumnSetIntervalTree.initIfNeeded();
     for (auto columnSet : m_multiColumnSetList)
         m_multiColumnSetIntervalTree.add(MultiColumnSetIntervalTree::createInterval(columnSet->logicalTopInFlowThread(), columnSet->logicalBottomInFlowThread(), columnSet));
 }
 
+LayoutUnit LayoutFlowThread::nextLogicalTopForUnbreakableContent(LayoutUnit flowThreadOffset, LayoutUnit contentLogicalHeight) const
+{
+    LayoutMultiColumnSet* columnSet = columnSetAtBlockOffset(flowThreadOffset);
+    if (!columnSet)
+        return flowThreadOffset;
+    return columnSet->nextLogicalTopForUnbreakableContent(flowThreadOffset, contentLogicalHeight);
+}
+
 void LayoutFlowThread::collectLayerFragments(PaintLayerFragments& layerFragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRectInFlowThread)
 {
     ASSERT(!m_columnSetsInvalidated);
 
     LayoutRect dirtyRectInMulticolContainer(dirtyRectInFlowThread);
     dirtyRectInMulticolContainer.moveBy(location());
 
     for (LayoutMultiColumnSetList::const_iterator iter = m_multiColumnSetList.begin(); iter != m_multiColumnSetList.end(); ++iter) {
         LayoutMultiColumnSet* columnSet = *iter;
         columnSet->collectLayerFragments(layerFragments, layerBoundingBox, dirtyRectInMulticolContainer);
@@ skipping 13 matching lines @@
 
 void LayoutFlowThread::MultiColumnSetSearchAdapter::collectIfNeeded(const MultiColumnSetInterval& interval)
 {
     if (m_result)
         return;
     if (interval.low() <= m_offset && interval.high() > m_offset)
         m_result = interval.data();
 }
 
 } // namespace blink