Add out-of-flow descendants of spanners to their containing blocks in time.

Source/core/layout/LayoutBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 1024 matching lines @@
 
 bool LayoutBlock::createsNewFormattingContext() const
 {
     return isInlineBlockOrInlineTable() || isFloatingOrOutOfFlowPositioned() || hasOverflowClip() || isFlexItemIncludingDeprecated()
         || style()->specifiesColumns() || isLayoutFlowThread() || isTableCell() || isTableCaption() || isFieldset() || isWritingModeRoot()
         || isDocumentElement() || isColumnSpanAll() || isGridItem();
 }
 
 void LayoutBlock::updateBlockChildDirtyBitsBeforeLayout(bool relayoutChildren, LayoutBox& child)
 {
+    if (child.isOutOfFlowPositioned()) {

[dsinclair, 2015/06/12 13:40:45]

Doesn't this mean that an out of flow child will never have the dirty bits
updated?

[mstensho (USE GERRIT), 2015/06/12 13:45:08]

The counterpart for out of flow objects seems to be in
LayoutBlock::layoutPositionedObjects(), wehre we do things like:

        if (relayoutChildren ||
needsLayoutDueToStaticPosition(positionedObject))
            layoutScope.setChildNeedsLayout(positionedObject);

and a bunch of other things.

+        // It's rather useless to mark out-of-flow children at this point. We may not be their
+        // containing block (and if we are, it's just pure luck), so this would be the wrong place
+        // for it. Furthermore, it would cause trouble for out-of-flow descendants of column
+        // spanners, if the containing block is outside the spanner but inside the multicol container.
+        return;
+    }
     // FIXME: Technically percentage height objects only need a relayout if their percentage isn't going to be turned into
     // an auto value. Add a method to determine this, so that we can avoid the relayout.
     bool hasRelativeLogicalHeight = child.hasRelativeLogicalHeight()
         || (child.isAnonymous() && this->hasRelativeLogicalHeight())
         || child.stretchesToViewport();
     if (relayoutChildren || (hasRelativeLogicalHeight && !isLayoutView()))
         child.setChildNeedsLayout(MarkOnlyThis);
 
     // If relayoutChildren is set and the child has percentage padding or an embedded content box, we also need to invalidate the childs pref widths.
     if (relayoutChildren && child.needsPreferredWidthsRecalculation())
@@ skipping 1852 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink