[css-grid] Store lines instead of tracks in GridResolvedPosition

third_party/WebKit/Source/core/paint/GridPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/GridPainter.h"
 
 #include "core/layout/LayoutGrid.h"
 #include "core/paint/BlockPainter.h"
 #include "core/paint/PaintInfo.h"
 
 namespace blink {
 
 static GridSpan dirtiedGridAreas(const Vector<LayoutUnit>& coordinates, LayoutUnit start, LayoutUnit end)
 {
     // This function does a binary search over the coordinates.
     // This doesn't work with grid items overflowing their grid areas, but that is managed with m_gridItemsOverflowingGridArea.
 
     size_t startGridAreaIndex = std::upper_bound(coordinates.begin(), coordinates.end() - 1, start) - coordinates.begin();
     if (startGridAreaIndex > 0)
         --startGridAreaIndex;
 
     size_t endGridAreaIndex = std::upper_bound(coordinates.begin() + startGridAreaIndex, coordinates.end() - 1, end) - coordinates.begin();
     if (endGridAreaIndex > 0)
         --endGridAreaIndex;
 
-    return GridSpan(startGridAreaIndex, endGridAreaIndex);
+    // GridSpan stores lines' indexes (not tracks' indexes).
+    return GridSpan(startGridAreaIndex, endGridAreaIndex + 1);
 }
 
 class GridItemsSorter {
 public:
     bool operator()(const std::pair<LayoutBox*, size_t>& firstChild, const std::pair<LayoutBox*, size_t>& secondChild) const
     {
         if (firstChild.first->style()->order() != secondChild.first->style()->order())
             return firstChild.first->style()->order() < secondChild.first->style()->order();
 
         return firstChild.second < secondChild.second;
@@ skipping 36 matching lines @@
         LayoutBox* current = gridItemAndPaintIndex.first;
         if (current == previous)
             continue;
 
         BlockPainter(m_layoutGrid).paintChildAsInlineBlock(*current, paintInfo, paintOffset);
         previous = current;
     }
 }
 
 } // namespace blink