[New Multicolumn] Actual support for layout of column-span:all.

Source/core/rendering/RenderFlowThread.h

 /*
  * 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 49 matching lines @@
     virtual bool isRenderFlowThread() const override final { return true; }
     virtual bool isRenderMultiColumnFlowThread() const { return false; }
     virtual bool isRenderPagedFlowThread() const { return false; }
 
     virtual void layout() override;
 
     // Always create a RenderLayer for the RenderFlowThread so that we
     // can easily avoid drawing the children directly.
     virtual LayerType layerTypeRequired() const override final { return NormalLayer; }
 
+    virtual bool isColumnSpanner(const RenderObject*) const { return false; }
+
+    // Is the specified renderer a column spanner or inside one?
+    virtual bool isInsideColumnSpanner(const RenderObject*) const { return false; }
+
+    virtual LayoutUnit enterColumnSpannerBeforeLayout(RenderBox*, LayoutUnit logicalTop, SubtreeLayoutScope&) { return LayoutUnit(); }
+    virtual void leaveColumnSpannerAfterLayout(RenderBox*, LayoutUnit logicalBottom) { }
     virtual void flowThreadDescendantWasInserted(RenderObject*) { }
 
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) override final;
 
     virtual void addRegionToThread(RenderMultiColumnSet*) = 0;
     virtual void removeRegionFromThread(RenderMultiColumnSet*);
 
     virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const override;
 
     bool hasRegions() const { return m_multiColumnSetList.size(); }
@@ skipping 29 matching lines @@
         return flowThreadPoint + columnOffset(flowThreadPoint);
     }
 
     void pushFlowThreadLayoutState(const RenderObject&);
     void popFlowThreadLayoutState();
     LayoutUnit offsetFromLogicalTopOfFirstRegion(const RenderBlock*) const;
 
     // Used to estimate the maximum height of the flow thread.
     static LayoutUnit maxLogicalHeight() { return LayoutUnit::max() / 2; }
 
+    virtual RenderMultiColumnSet* columnSetAtBlockOffset(LayoutUnit) const = 0;

[mstensho (USE GERRIT), 2014/11/07 16:06:01]

Note: made this public to be able to write a unit test for it. While it would be
nice to encapsulate RenderMultiColumnSet, so that e.g. RenderBlockFlow doesn't
get tempted to use it, there were already public getters for
RenderMultiColumnSet here, so it doesn't make much of a difference.

+
 protected:
     virtual const char* renderName() const = 0;
 
     void updateRegionsFlowThreadPortionRect();
     bool shouldIssuePaintInvalidations(const LayoutRect&) const;
 
-    virtual RenderMultiColumnSet* columnSetAtBlockOffset(LayoutUnit) const = 0;
-
     bool cachedOffsetFromLogicalTopOfFirstRegion(const RenderBox*, LayoutUnit&) const;
     void setOffsetFromLogicalTopOfFirstRegion(const RenderBox*, LayoutUnit);
     void clearOffsetFromLogicalTopOfFirstRegion(const RenderBox*);
 
     const RenderBox* currentStatePusherRenderBox() const;
 
     RenderMultiColumnSetList m_multiColumnSetList;
 
     typedef PODInterval<LayoutUnit, RenderMultiColumnSet*> MultiColumnSetInterval;
     typedef PODIntervalTree<LayoutUnit, RenderMultiColumnSet*> MultiColumnSetIntervalTree;
 
-    class RegionSearchAdapter {
+    class MultiColumnSetSearchAdapter {
     public:
-        RegionSearchAdapter(LayoutUnit offset)
+        MultiColumnSetSearchAdapter(LayoutUnit offset)
             : m_offset(offset)
             , m_result(0)
         {
         }
 
         const LayoutUnit& lowValue() const { return m_offset; }
         const LayoutUnit& highValue() const { return m_offset; }
         void collectIfNeeded(const MultiColumnSetInterval&);
 
-        RenderRegion* result() const { return m_result; }
+        RenderMultiColumnSet* result() const { return m_result; }
 
     private:
         LayoutUnit m_offset;
-        RenderRegion* m_result;
+        RenderMultiColumnSet* m_result;
     };
 
     // Stack of objects that pushed a LayoutState object on the RenderView. The
     // objects on the stack are the ones that are curently in the process of being
     // laid out.
     ListHashSet<const RenderObject*> m_statePusherObjectsStack;
     typedef HashMap<const RenderBox*, LayoutUnit> RenderBoxToOffsetMap;
     RenderBoxToOffsetMap m_boxesToOffsetMap;
 
     MultiColumnSetIntervalTree m_multiColumnSetIntervalTree;
@@ skipping 22 matching lines @@
 };
 
 template <> struct ValueToString<RenderMultiColumnSet*> {
     static String string(const RenderMultiColumnSet* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace blink
 
 #endif // RenderFlowThread_h