[css-grid] Clamp the number of auto-repeat tracks

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 2024 matching lines @@
   size_t repetitions =
       1 + (freeSpace / (autoRepeatTracksSize + gapSize)).toInt();
 
   // Provided the grid container does not have a definite size or max-size in
   // the relevant axis, if the min size is definite then the number of
   // repetitions is the largest possible positive integer that fulfills that
   // minimum requirement.
   if (needsToFulfillMinimumSize)
     ++repetitions;
 
+  // Clamp the number of repetitions so we don't end up with too many tracks

[Manuel Rego, 2017/01/27 09:05:57]

Nit: Missing dot after comment.

+  if (repetitions > kGridMaxTracks) {
+    repetitions =
+        (kGridMaxTracks - trackSizes.size()) / autoRepeatTrackListLength;

[eae, 2017/01/26 17:07:23]

I know we early return if autoRepeatTrackListLength is zero but that is over
three hundred lines away and might change. Would you mind adding a
DCHECK(autoRepeatTrackListLength) here?

+  }
+
   return repetitions * autoRepeatTrackListLength;
 }
 
 std::unique_ptr<LayoutGrid::OrderedTrackIndexSet>
 LayoutGrid::computeEmptyTracksForAutoRepeat(
     Grid& grid,
     GridTrackSizingDirection direction) const {
   bool isRowAxis = direction == ForColumns;
   if ((isRowAxis && styleRef().gridAutoRepeatColumnsType() != AutoFit) ||
       (!isRowAxis && styleRef().gridAutoRepeatRowsType() != AutoFit))
@@ skipping 1566 matching lines @@
   if (direction == ForRows)
     return grid.numTracks(ForRows);
 
   return grid.numTracks(ForRows)
              ? grid.numTracks(ForColumns)
              : GridPositionsResolver::explicitGridColumnCount(
                    styleRef(), grid.autoRepeatTracks(ForColumns));
 }
 
 }  // namespace blink