[New Multicolumn] mapAbsoluteToLocalPoint() needs to convert to flow thread coordinates.

Source/core/layout/LayoutMultiColumnFlowThread.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
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 }
 
 bool LayoutMultiColumnFlowThread::needsNewWidth() const
 {
     LayoutUnit newWidth;
     unsigned dummyColumnCount; // We only care if used column-width changes.
     calculateColumnCountAndWidth(newWidth, dummyColumnCount);
     return newWidth != logicalWidth();
 }
 
+LayoutPoint LayoutMultiColumnFlowThread::visualPointToFlowThreadPoint(const LayoutPoint& visualPoint) const
+{
+    LayoutUnit blockOffset = isHorizontalWritingMode() ? visualPoint.y() : visualPoint.x();
+    const LayoutMultiColumnSet* columnSet = nullptr;
+    for (const LayoutMultiColumnSet* candidate = firstMultiColumnSet(); candidate; candidate = candidate->nextSiblingMultiColumnSet()) {
+        columnSet = candidate;
+        if (candidate->logicalBottom() > blockOffset)
+            break;
+    }
+    return columnSet ? columnSet->visualPointToFlowThreadPoint(toLayoutPoint(visualPoint + location() - columnSet->location())) : visualPoint;
+}
+
 LayoutMultiColumnSet* LayoutMultiColumnFlowThread::columnSetAtBlockOffset(LayoutUnit offset) const
 {
     if (m_lastSetWorkedOn) {
         // Layout in progress. We are calculating the set heights as we speak, so the column set range
         // information is not up-to-date.
         return m_lastSetWorkedOn;
     }
 
     ASSERT(!m_regionsInvalidated);
     if (m_multiColumnSetList.isEmpty())
@@ skipping 448 matching lines @@
 }
 
 bool LayoutMultiColumnFlowThread::isPageLogicalHeightKnown() const
 {
     if (LayoutMultiColumnSet* columnSet = lastMultiColumnSet())
         return columnSet->pageLogicalHeight();
     return false;
 }
 
 }