[css-sizing-3] Revert commit that made block-axis min/max-content compute to 'auto'. 'auto' invokes too much magic, and this precludes non-flow layouts from doing useful things with min/max-content. #3973.

Author: tabatkins

css-sizing-3/Overview.bs

@@ -234,7 +234,7 @@ Auto Box Sizes</h3>
 
 			: <dfn>min-content block size</dfn>
 			:: In general,
-				and definitely for block-level and inline-level boxes,
+				and definitely for [=block containers=], tables, and [=inline boxes=],
 				this is equivalent to the <a>max-content block size</a>.
 
 		<dt><dfn>fit-content size</dfn>
@@ -248,7 +248,7 @@ Auto Box Sizes</h3>
 			Note: This is called the “shrink-to-fit” width in <a href="https://www.w3.org/TR/CSS2/visudet.html#float-width">CSS2.1§10.3.5</a>
 			and <a href="https://www.w3.org/TR/css3-multicol/#pseudo-algorithm">CSS Multi-column Layout § 3.4</a>.
 
-		<dd><dfn>intrinsic size</dfn>
+		<dt><dfn>intrinsic size</dfn>
 		<dd>
 			A <a>max-content size</a> or <a>min-content size</a>,
 			i.e. a size arising primarily from the size of the content.
@@ -446,30 +446,28 @@ Sizing Values: the <<length-percentage>>, ''width/auto'' | ''max-width/none'', '
 		<dd>
 			If specified for the inline axis,
 			use the <a>min-content inline size</a>;
-			otherwise behaves as the property’s <a>initial value</a>.
+			otherwise compute to ''width/auto''.
 
 		<dt><dfn>max-content</dfn>
 		<dd>
 			If specified for the inline axis,
 			use the <a>max-content inline size</a>;
-			otherwise behaves as the property’s <a>initial value</a>.
+			otherwise compute to ''width/auto''.
 <!--
 		<dt><dfn>fit-content</dfn>
 		<dd>
-			If specified for the inline axis,
-			use the <a>fit-content inline size</a>
+			Use the <a>fit-content inline size</a> or <a>fit-content block size</a>,
+			as appropriate to the writing mode,
 			i.e.
-			<code>min(''width/max-content'', max(''width/min-content'', ''width/stretch''))</code>;
-			otherwise behaves as the property’s <a>initial value</a>.
+			<code>min(''width/max-content'', max(''width/min-content'', ''width/stretch''))</code>.
 -->
 		<dt><dfn>fit-content(<<length-percentage>>)</dfn>
 		<dd>
-			If specified for the inline axis,
-			use the fit-content formula
+			Use the fit-content formula
 			with the <a>available space</a> replaced by the specified argument,
 			i.e.
-			<code>min(''width/max-content'', max(''width/min-content'', <<length-percentage>>))</code>;
-			otherwise behaves as the property’s <a>initial value</a>.
+			<code>min(''width/max-content'', max(''width/min-content'', <<length-percentage>>))</code>.
+
 			For <a>intrinsic size contributions</a>,
 			''fit-content(<<length>>)'' behaves as the resulting length;
 			''width/fit-content()'' containing a <<percentage>> behaves