Add some better documentation to LayoutObject

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 830 matching lines @@
     // Our intrinsic height, used for min-height: min-content etc. Maintained by
     // updateLogicalHeight. This is logicalHeight() before it is clamped to
     // min/max.
     mutable LayoutUnit m_intrinsicContentLogicalHeight;
 
     void inflatePaintInvalidationRectForReflectionAndFilter(LayoutRect&) const;
 
     LayoutRectOutsets m_marginBoxOutsets;
 
 protected:
-    // The preferred logical width of the element if it were to break its lines at every possible opportunity.
+    // The preferred logical width of the element if it were to break its lines at every
+    // possible opportunity. CSS 2.1 calls this width the "preferred minimum width" and
+    // "minimum content width".
+    // See https://drafts.csswg.org/css-sizing-3/#intrinsic for more information.
     LayoutUnit m_minPreferredLogicalWidth;
 
     // The preferred logical width of the element if it never breaks any lines at all.
+    // CSS 2.1 calls this width the "preferred width" and "maximum cell width".
+    // See https://drafts.csswg.org/css-sizing-3/#intrinsic for more information.
     LayoutUnit m_maxPreferredLogicalWidth;
 
     // Our overflow information.
     OwnPtr<OverflowModel> m_overflow;
 
 private:
     OwnPtr<LayoutBoxRareData> m_rareData;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBox, isBox());
@@ skipping 65 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != nullptr))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // LayoutBox_h