[css-contain] iteration between containment and baseline alignment

Closes w3c#2995

Author: frivoal

css-contain-1/Overview.bs

@@ -188,7 +188,7 @@ Size Containment</h3>
 	size containment has no effect.
 	Otherwise, giving an element <dfn export>size containment</dfn> has the following effects:
 
-	1. When laying out the containing element,
+	1. When calculating the size of the containing element,
 		it must be treated as having no contents.
 
 		Note: Even when the element's [=sizing properties=] are ''height/auto''
@@ -197,9 +197,12 @@ Size Containment</h3>
 		such as the 'columns' property or the 'grid' property,
 		continue to be taken into account.
 
-		After layout of the element is complete,
+		Then,
 		its contents must then be laid out into the containing element's resolved size.
 
+		Note: [=size containment=] does not suppress baseline alignment.
+		See [=layout containment=] for that.
+
 		<a>Replaced elements</a> must be treated as having an intrinsic width and height of 0.
 	2. Elements with <a>size containment</a> are <a spec=css-break-3>monolithic</a> (See [[CSS-BREAK-3#possible-breaks]]).
 
@@ -312,6 +315,12 @@ Layout Containment</h3>
 		Note: This introduces the previously non-existent possibility that [=forced breaks=]
 		may occur between a box and its container (See [[CSS-BREAK-3#possible-breaks]]).
 
+	7. For the purpose of the 'vertical-align' property,
+		or any other property whose effects
+		need to relate the position of the containing element's baseline
+		to something other than its descendants,
+		the containing element is treated as having no baseline.
+
 	Possible optimizations that can be enabled by <a>layout containment</a> include (but are not limited to):
 
 	1. When laying out the page,
@@ -516,6 +525,7 @@ This appendix is <em>informative</em>.
 <h3 id="2018-05-24-changes">Changes from the
 <a href="https://www.w3.org/TR/2018/CR-css-contain-1-20180524/">Candidate Recommendation of 24 May 2018</a></h3>
 
+* Layout containment suppresses baseline alignement, but size containment does not
 * Layout containment causes the element to establish a new stacking context
 * Size containment does not apply to tables
 * Clarify that the columns and grid properties affect the size of size-contained elements

css-contain-1/issues-2018-cr.html

@@ -92,6 +92,15 @@ <h1>CSS Contain Level 1 Disposition of Comments for 2018-05-24 CR</h1>
 Response: <a href='https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-408244344'>https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-408244344</a>
 Closed:   Accepted
 Resolved: <a href='https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-409762755'>https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-409762755</a></pre>
+<pre class='a' id='issue-8'>
+Issue 8. <a href='#issue-8'>#</a>
+Summary:  containment vs baseline alignement
+From:     Florian Rivoal
+Comment:  <a href='https://github.com/w3c/csswg-drafts/issues/2995'>https://github.com/w3c/csswg-drafts/issues/2995</a>
+Comment:  <a href='https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411126837'>https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411126837</a>
+Response: <a href='https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411371226'>https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411371226</a>
+Closed:   Accepted
+Resolved: <a href='https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-415094473'>https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-415094473</a></pre>
 <script>
 (function () {
     var sheet = document.styleSheets[0];

css-contain-1/issues-2018-cr.txt

@@ -62,3 +62,12 @@ Response: https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-407956323
 Response: https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-408244344
 Closed:   Accepted
 Resolved: https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-409762755
+----
+Issue 8.
+Summary:  containment vs baseline alignement
+From:     Florian Rivoal
+Comment:  https://github.com/w3c/csswg-drafts/issues/2995
+Comment:  https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411126837
+Response: https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-411371226
+Closed:   Accepted
+Resolved: https://github.com/w3c/csswg-drafts/issues/2995#issuecomment-415094473