Add support for printing multicol containers, and enable it.

third_party/WebKit/Source/core/layout/LayoutMultiColumnSet.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 83 matching lines @@
 }
 
 bool LayoutMultiColumnSet::isPageLogicalHeightKnown() const
 {
     return firstFragmentainerGroup().logicalHeight();
 }
 
 LayoutUnit LayoutMultiColumnSet::nextLogicalTopForUnbreakableContent(LayoutUnit flowThreadOffset, LayoutUnit contentLogicalHeight) const
 {
     ASSERT(pageLogicalTopForOffset(flowThreadOffset) == flowThreadOffset);
-    LayoutMultiColumnFlowThread* enclosingFlowThread = multiColumnFlowThread()->enclosingFlowThread();
-    if (!enclosingFlowThread) {
+    FragmentationContext* enclosingFragmentationContext = multiColumnFlowThread()->enclosingFragmentationContext();
+    if (!enclosingFragmentationContext) {
         // If there's no enclosing fragmentation context, there'll ever be only one row, and all
         // columns there will have the same height.
         return flowThreadOffset;
     }
 
     // Assert the problematic situation. If we have no problem with the column height, why are we
     // even here?
     ASSERT(pageLogicalHeightForOffset(flowThreadOffset) < contentLogicalHeight);
 
     // There's a likelihood for subsequent rows to be taller than the first one.
     // TODO(mstensho): if we're doubly nested (e.g. multicol in multicol in multicol), we need to
     // look beyond the first row here.
     const MultiColumnFragmentainerGroup& firstRow = firstFragmentainerGroup();
     LayoutUnit firstRowLogicalBottomInFlowThread = firstRow.logicalTopInFlowThread() + firstRow.logicalHeight() * usedColumnCount();
     if (flowThreadOffset >= firstRowLogicalBottomInFlowThread)
         return flowThreadOffset; // We're not in the first row. Give up.
-    LayoutUnit newLogicalHeight = enclosingFlowThread->pageLogicalHeightForOffset(firstRowLogicalBottomInFlowThread);
+    LayoutUnit newLogicalHeight = enclosingFragmentationContext->fragmentainerLogicalHeightAt(firstRowLogicalBottomInFlowThread);
     if (contentLogicalHeight > newLogicalHeight) {
         // The next outer column or page doesn't have enough space either. Give up and stay where
         // we are.
         return flowThreadOffset;
     }
     return firstRowLogicalBottomInFlowThread;
 }
 
 LayoutMultiColumnSet* LayoutMultiColumnSet::nextSiblingMultiColumnSet() const
 {
@@ skipping 115 matching lines @@
     return row.visualPointToFlowThreadPoint(visualPoint - row.offsetFromColumnSet());
 }
 
 LayoutUnit LayoutMultiColumnSet::pageLogicalTopForOffset(LayoutUnit offset) const
 {
     return fragmentainerGroupAtFlowThreadOffset(offset).columnLogicalTopForOffset(offset);
 }
 
 bool LayoutMultiColumnSet::recalculateColumnHeight()
 {
-    if (m_oldLogicalTop != logicalTop() && multiColumnFlowThread()->enclosingFlowThread()) {
+    if (m_oldLogicalTop != logicalTop() && multiColumnFlowThread()->enclosingFragmentationContext()) {
         // Preceding spanners or column sets have been moved or resized. This means that the
         // fragmentainer groups that we have inserted need to be re-inserted. Restart column
         // balancing.
         resetColumnHeight();
         return true;
     }
 
     bool changed = false;
     for (auto& group : m_fragmentainerGroups)
         changed = group.recalculateColumnHeight() || changed;
@@ skipping 129 matching lines @@
 
 LayoutRect LayoutMultiColumnSet::flowThreadPortionRect() const
 {
     LayoutRect portionRect(LayoutUnit(), logicalTopInFlowThread(), pageLogicalWidth(), logicalHeightInFlowThread());
     if (!isHorizontalWritingMode())
         return portionRect.transposedRect();
     return portionRect;
 }
 
 }