[css-values-5] Remove the single-argument form of calc-size().

This removes the one-argument form of calc-size() and leaves only the
two-argument form, as resolved in
w3c#10478

Author: dbaron

css-values-5/Overview.bs

@@ -1734,7 +1734,7 @@ allows math to be performed on intrinsic sizes
 in a safe, well-defined way.
 
 	<pre class=prod>
-	<dfn function lt="calc-size()">&lt;calc-size()></dfn> = calc-size( <<calc-size-basis>>, <<calc-sum>>? )
+	<dfn function lt="calc-size()">&lt;calc-size()></dfn> = calc-size( <<calc-size-basis>>, <<calc-sum>> )
 
 	<dfn>&lt;calc-size-basis></dfn> = [ <<intrinsic-size-keyword>> | percentage | <<calc-size()>> | any | <<calc-sum>> ]
 	</pre>
@@ -1767,20 +1767,12 @@ indicates a basis size of ''100%''.
 	see [[#simplifying-calc-size]].
 </details>
 
-If two arguments are given,
-the first is the <dfn>calc-size basis</dfn>,
+The first argument given is the <dfn>calc-size basis</dfn>,
 and the second is the <dfn>calc-size calculation</dfn>.
 For either argument,
 if a <<calc-sum>> is given,
 it must resolve to a <<length>>.
 
-If only one argument is given,
-and it's a <<calc-sum>>,
-then the provided argument is the [=calc-size calculation=],
-and the [=calc-size basis=] defaults to ''calc-size()/any''.
-Otherwise, the provided argument is the [=calc-size basis=],
-and the [=calc-size calculation=] defaults to ''calc-size()/size''.
-
 Within the [=calc-size calculation=],
 if the [=calc-size basis=] is not ''calc-size()/any'',
 the keyword <dfn for=calc-size() value>size</dfn> is allowed.
@@ -2032,7 +2024,8 @@ with a <<length-percentage>> or an <<intrinsic-size-keyword>>.
 To determine whether the values can interpolate
 and what the interpolation behavior is,
 treat the non-''calc-size()'' value
-as ''calc-size( <var ignore>value</var> )''
+as ''calc-size(any,  <var ignore>value</var> )'' if the value is a <<calc-sum>>
+or as ''calc-size( <var ignore>value</var> , size)'' otherwise,
 and apply the rules above.
 
 <div class=example>
@@ -2049,7 +2042,7 @@ and apply the rules above.
 		height: auto;
 	}
 	details:not([open])::details-content {
-		height: calc-size(0px);
+		height: calc-size(any, 0px);
 	}
 	</pre>
 
@@ -2063,7 +2056,7 @@ and apply the rules above.
 </div>
 
 Note: ''calc-size()'' is designed such that
-transitioning to/from ''calc-size([=definite=] length)''
+transitioning to/from ''calc-size(any, [=definite=] length)''
 will <em>always</em> work smoothly,
 regardless of how the other side of the transition is specified.
 

css-values-5/calc-size-explainer.md

@@ -122,17 +122,6 @@ this would be a normal intermediate value at 70% of the way through an animation
 
 This is specified [in css-values-5](https://drafts.csswg.org/css-values-5/#calc-size).
 
-## `calc-size(<value>)`
-
-`calc-size()` also has a single-argument form.
-If that single argument is an intrinsic sizing keyword or a `calc-size()` function,
-then the argument is treated as the `<basis>` and the calculation is `size`.
-Otherwise the single argument is a `<calc-sum>` expression that is treated as the calculation,
-and the basis is `any`.
-
-This form makes it more convenient to opt in to animation using `calc-size()`
-by wrapping at least one endpoint of the animation in `calc-size()`.
-
 The following slightly more involved example shows
 (while using the separately proposed `::details-content` pseudo-element)
 the CSS needed to make a `<details>` element
@@ -147,7 +136,7 @@ details::details-content {
               content-visibility var(--open-close-duration) allow-discrete;
 }
 details[open]::details-content {
-  height: calc-size(max-content);
+  height: calc-size(max-content, size);
 }
 ```