Div having contentEditable and display:grid cannot be edited if it is empty.

Source/core/layout/LayoutBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 90 matching lines @@
     LayoutUnit logicalWidth() const { return style()->isHorizontalWritingMode() ? m_frameRect.width() : m_frameRect.height(); }
     LayoutUnit logicalHeight() const { return style()->isHorizontalWritingMode() ? m_frameRect.height() : m_frameRect.width(); }
 
     LayoutUnit constrainLogicalWidthByMinMax(LayoutUnit, LayoutUnit, LayoutBlock*) const;
     LayoutUnit constrainLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const;
     LayoutUnit constrainContentBoxLogicalHeightByMinMax(LayoutUnit logicalHeight, LayoutUnit intrinsicContentHeight) const;
 
     int pixelSnappedLogicalHeight() const { return style()->isHorizontalWritingMode() ? pixelSnappedHeight() : pixelSnappedWidth(); }
     int pixelSnappedLogicalWidth() const { return style()->isHorizontalWritingMode() ? pixelSnappedWidth() : pixelSnappedHeight(); }
 
+    LayoutUnit minimumLogicalHeightForEmptyLine() const
+    {
+        return borderAndPaddingLogicalHeight() + scrollbarLogicalHeight()
+            + lineHeight(true, isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
+    }
+
     void setLogicalLeft(LayoutUnit left)
     {
         if (style()->isHorizontalWritingMode())
             setX(left);
         else
             setY(left);
     }
     void setLogicalTop(LayoutUnit top)
     {
         if (style()->isHorizontalWritingMode())
@@ skipping 724 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // LayoutBox_h