[css-grid] Protect against negative values in applyStretchAlignmentToChildIfNeeded()

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 1455 matching lines @@
                             : allowedToStretchChildAlongRowAxis(child);
   if (allowedToStretchChildBlockSize) {
     LayoutUnit stretchedLogicalHeight =
         availableAlignmentSpaceForChildBeforeStretching(
             overrideContainingBlockContentSizeForChild(child,
                                                        childBlockDirection),
             child);
     LayoutUnit desiredLogicalHeight = child.constrainLogicalHeightByMinMax(
         stretchedLogicalHeight, LayoutUnit(-1));
     child.setOverrideLogicalContentHeight(
-        desiredLogicalHeight - child.borderAndPaddingLogicalHeight());
+        std::max(desiredLogicalHeight - child.borderAndPaddingLogicalHeight(),
+                 LayoutUnit()));

[svillar, 2017/03/09 10:29:15]

clampNegativeToZero()

[Manuel Rego, 2017/03/09 10:59:13]

Done.

     if (desiredLogicalHeight != child.logicalHeight()) {
       // TODO (lajava): Can avoid laying out here in some cases. See
       // https://webkit.org/b/87905.
       child.setLogicalHeight(LayoutUnit());
       child.setNeedsLayout(LayoutInvalidationReason::GridChanged);
     }
   }
 }
 
 // TODO(lajava): This logic is shared by LayoutFlexibleBox, so it should be
@@ skipping 608 matching lines @@
   if (direction == ForRows)
     return grid.numTracks(ForRows);
 
   return grid.numTracks(ForRows)
              ? grid.numTracks(ForColumns)
              : GridPositionsResolver::explicitGridColumnCount(
                    styleRef(), grid.autoRepeatTracks(ForColumns));
 }
 
 }  // namespace blink