[New Multicolumn] Let a spanner's containing block be the multicol container.

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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
@@ skipping 34 matching lines @@
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderDeprecatedFlexibleBox.h"
 #include "core/rendering/RenderFlexibleBox.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderGrid.h"
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderListBox.h"
 #include "core/rendering/RenderListMarker.h"
+#include "core/rendering/RenderMultiColumnSpannerPlaceholder.h"
 #include "core/rendering/RenderTableCell.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "platform/LengthFunctions.h"
 #include "platform/geometry/FloatQuad.h"
 #include "platform/geometry/TransformState.h"
 #include <algorithm>
 #include <math.h>
 
 namespace blink {
@@ skipping 27 matching lines @@
 
 RenderBox::RenderBox(ContainerNode* node)
     : RenderBoxModelObject(node)
     , m_intrinsicContentLogicalHeight(-1)
     , m_minPreferredLogicalWidth(-1)
     , m_maxPreferredLogicalWidth(-1)
 {
     setIsBox();
 }
 
+void RenderBox::willBeRemovedFromTree()
+{
+    if (m_rareData && m_rareData->m_spannerPlaceholder) {
+        m_rareData->m_spannerPlaceholder->spannerWillBeRemoved();
+        m_rareData->m_spannerPlaceholder = 0;
+    }
+    RenderBoxModelObject::willBeRemovedFromTree();
+}
+
 void RenderBox::willBeDestroyed()
 {
     clearOverrideSize();
     clearContainingBlockOverrideSize();
 
     RenderBlock::removePercentHeightDescendantIfNeeded(this);
 
     ShapeOutsideInfo::removeInfo(*this);
 
     RenderBoxModelObject::willBeDestroyed();
@@ skipping 1539 matching lines @@
 {
     if (inlineBoxWrapper()) {
         if (!documentBeingDestroyed())
             inlineBoxWrapper()->remove();
         inlineBoxWrapper()->destroy();
         ASSERT(m_rareData);
         m_rareData->m_inlineBoxWrapper = 0;
     }
 }
 
+void RenderBox::setSpannerPlaceholder(RenderMultiColumnSpannerPlaceholder& placeholder)
+{
+    RELEASE_ASSERT(!m_rareData || !m_rareData->m_spannerPlaceholder); // not expected to change directly from one spanner to another.
+    ensureRareData().m_spannerPlaceholder = &placeholder;
+}
+
+void RenderBox::clearSpannerPlaceholder()
+{
+    if (!m_rareData)
+        return;
+    m_rareData->m_spannerPlaceholder = 0;
+}
+
 LayoutRect RenderBox::clippedOverflowRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
 {
     if (style()->visibility() != VISIBLE) {
         RenderLayer* layer = enclosingLayer();
         layer->updateDescendantDependentFlags();
         if (layer->subtreeIsInvisible())
             return LayoutRect();
     }
 
     LayoutRect r = visualOverflowRect();
@@ skipping 2758 matching lines @@
     computedValues.m_margins.m_end = marginEnd();
 
     setLogicalTop(oldLogicalTop);
     setLogicalWidth(oldLogicalWidth);
     setLogicalLeft(oldLogicalLeft);
     setMarginLeft(oldMarginLeft);
     setMarginRight(oldMarginRight);
 }
 
 } // namespace blink