[css-grid] grid-auto-flow|row should take a <track-size>+

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 830 matching lines @@
     if (direction == ForColumns)
         return child.hasRelativeLogicalWidth() || child.styleRef().logicalWidth().isIntrinsicOrAuto();
     return child.hasRelativeLogicalHeight() || child.styleRef().logicalHeight().isIntrinsicOrAuto();
 }
 
 const GridTrackSize& LayoutGrid::rawGridTrackSize(GridTrackSizingDirection direction, size_t translatedIndex) const
 {
     bool isRowAxis = direction == ForColumns;
     const Vector<GridTrackSize>& trackStyles = isRowAxis ? styleRef().gridTemplateColumns() : styleRef().gridTemplateRows();
     const Vector<GridTrackSize>& autoRepeatTrackStyles = isRowAxis ? styleRef().gridAutoRepeatColumns() : styleRef().gridAutoRepeatRows();
-    const GridTrackSize& autoTrackSize = isRowAxis ? styleRef().gridAutoColumns() : styleRef().gridAutoRows();
+    const Vector<GridTrackSize>& autoTrackStyles = isRowAxis ? styleRef().gridAutoColumns() : styleRef().gridAutoRows();
     size_t insertionPoint = isRowAxis ? styleRef().gridAutoRepeatColumnsInsertionPoint() : styleRef().gridAutoRepeatRowsInsertionPoint();
     size_t repetitions = autoRepeatCountForDirection(direction);
 
     // We should not use GridPositionsResolver::explicitGridXXXCount() for this because the
     // explicit grid might be larger than the number of tracks in grid-template-rows|columns (if
     // grid-template-areas is specified for example).
     size_t explicitTracksCount = trackStyles.size() + repetitions;
 
     int untranslatedIndexAsInt = translatedIndex + (isRowAxis ? m_smallestColumnStart : m_smallestRowStart);
-    if (untranslatedIndexAsInt < 0)
-        return autoTrackSize;
+    if (untranslatedIndexAsInt < 0) {
+        size_t autoTrackStylesSize = autoTrackStyles.size();

[Manuel Rego, 2016/07/22 08:24:55]

What about defining it as an int to avoid the cast later?

Nit: You can move this out of the if and use it later.

[svillar, 2016/07/22 13:08:28]

We're using it as size_t later anyway.
OK

+        int index = untranslatedIndexAsInt % static_cast<int>(autoTrackStylesSize);
+        // We need to traspose the index because the first negative implicit line will get the last defined auto track and so on.
+        index += index ? autoTrackStylesSize : 0;
+        return autoTrackStyles[index];
+    }
 
     size_t untranslatedIndex = static_cast<size_t>(untranslatedIndexAsInt);
     if (untranslatedIndex >= explicitTracksCount)
-        return autoTrackSize;
+        return autoTrackStyles[(untranslatedIndex - explicitTracksCount) % autoTrackStyles.size()];
 
     if (LIKELY(!repetitions) || untranslatedIndex < insertionPoint)
         return trackStyles[untranslatedIndex];
 
     if (untranslatedIndex < (insertionPoint + repetitions))
         return autoRepeatTrackStyles[0];
 
     return trackStyles[untranslatedIndex - repetitions];
 }
 
@@ skipping 1662 matching lines @@
     return isOrthogonalChild(child) ? childLocation.transposedPoint() : childLocation;
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     if (!m_gridItemArea.isEmpty())
         GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink