Add some better documentation to LayoutObject

Source/core/layout/LayoutBox.h

Index: Source/core/layout/LayoutBox.h
diff --git a/Source/core/layout/LayoutBox.h b/Source/core/layout/LayoutBox.h
index 2a00d921812cd23eb2aae0a3d5b82a4fc1d588e9..348d5eeca8b3971bf21004e977813c12a6fc2e98 100644
--- a/Source/core/layout/LayoutBox.h
+++ b/Source/core/layout/LayoutBox.h
@@ -848,10 +848,15 @@ private:
     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.