[css-grid] Fix alignment with content distribution

third_party/WebKit/Source/core/layout/LayoutGrid.cpp

 /*
  * Copyright (C) 2011 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
@@ skipping 1949 matching lines @@
     if (hasAutoMarginsInColumnAxis(child))
         return startPosition;
     GridAxisPosition axisPosition = columnAxisPositionForChild(child);
     switch (axisPosition) {
     case GridAxisStart:
         return startPosition;
     case GridAxisEnd:
     case GridAxisCenter: {
         size_t childEndLine = rowsSpan.endLine();
         LayoutUnit endOfRow = m_rowPositions[childEndLine];
-        // m_rowPositions include gutters so we need to subtract them to get the actual end position for a given
-        // row (this does not have to be done for the last track as there are no more m_rowPositions after it)
+        // m_rowPositions include distribution offset (because of content alignment) and gutters
+        // so we need to subtract them to get the actual end position for a given row
+        // (this does not have to be done for the last track as there are no more m_columnPositions after it).
         LayoutUnit trackGap = guttersSize(ForRows, 2);
-        if (childEndLine < m_rowPositions.size() - 1)
+        if (childEndLine < m_rowPositions.size() - 1) {
             endOfRow -= trackGap;
+            endOfRow -= m_offsetBetweenRows;
+        }
         LayoutUnit childBreadth = child.logicalHeight() + child.marginLogicalHeight();
-        // The track's start and end lines may be not adjacent because of content alignment, so we assume the stored
-        // lines are all start plus a content-alignment distribution offset.
-        // We must subtract last line's offset because is not part of the track the items belongs to.
-        if (childEndLine - childStartLine > 1 && childEndLine < m_rowPositions.size() - 1)
-            endOfRow -= m_offsetBetweenRows;
         OverflowAlignment overflow = child.styleRef().resolvedAlignment(styleRef(), ItemPositionStretch).overflow();
         LayoutUnit offsetFromStartPosition = computeOverflowAlignmentOffset(overflow, endOfRow - startOfRow, childBreadth);
         return startPosition + (axisPosition == GridAxisEnd ? offsetFromStartPosition : offsetFromStartPosition / 2);
     }
     }
 
     ASSERT_NOT_REACHED();
     return LayoutUnit();
 }
 
 LayoutUnit LayoutGrid::rowAxisOffsetForChild(const LayoutBox& child, GridSizingData& sizingData) const
 {
     const GridSpan& columnsSpan = cachedGridSpan(child, ForColumns);
     size_t childStartLine = columnsSpan.startLine();
     LayoutUnit startOfColumn = m_columnPositions[childStartLine];
     LayoutUnit startPosition = startOfColumn + marginStartForChild(child);
     if (hasAutoMarginsInRowAxis(child))
         return startPosition;
     GridAxisPosition axisPosition = rowAxisPositionForChild(child);
     switch (axisPosition) {
     case GridAxisStart:
         return startPosition;
     case GridAxisEnd:
     case GridAxisCenter: {
         size_t childEndLine = columnsSpan.endLine();
         LayoutUnit endOfColumn = m_columnPositions[childEndLine];
-        // m_columnPositions include gutters so we need to subtract them to get the actual end position for a given
-        // column (this does not have to be done for the last track as there are no more m_columnPositions after it)
+        // m_columnPositions include distribution offset (because of content alignment) and gutters
+        // so we need to subtract them to get the actual end position for a given column
+        // (this does not have to be done for the last track as there are no more m_columnPositions after it).
         LayoutUnit trackGap = guttersSize(ForColumns, 2);
-        if (childEndLine < m_columnPositions.size() - 1)
+        if (childEndLine < m_columnPositions.size() - 1) {
             endOfColumn -= trackGap;
+            endOfColumn -= m_offsetBetweenColumns;
+        }
         LayoutUnit childBreadth = child.logicalWidth() + child.marginLogicalWidth();
-        // The track's start and end lines may be not adjacent because of content alignment, so we assume the stored
-        // lines are all start plus a content-alignment distribution offset.
-        // We must subtract last line's offset because is not part of the track the items belongs to.
-        if (childEndLine - childStartLine > 1 && childEndLine < m_columnPositions.size() - 1)
-            endOfColumn -= m_offsetBetweenColumns;
         LayoutUnit offsetFromStartPosition = computeOverflowAlignmentOffset(child.styleRef().justifySelfOverflowAlignment(), endOfColumn - startOfColumn, childBreadth);
         return startPosition + (axisPosition == GridAxisEnd ? offsetFromStartPosition : offsetFromStartPosition / 2);
     }
     }
 
     ASSERT_NOT_REACHED();
     return LayoutUnit();
 }
 
 ContentPosition static resolveContentDistributionFallback(ContentDistributionType distribution)
@@ skipping 110 matching lines @@
 
     return LayoutPoint(rowAxisOffset, columnAxisOffsetForChild(child, sizingData));
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink