[css-contain] Add note on size containment and table captions

Closes w3c#2952

Author: frivoal

css-contain-1/Overview.bs

@@ -188,6 +188,19 @@ Size Containment</h3>
 	size containment has no effect.
 	Otherwise, giving an element <dfn export>size containment</dfn> has the following effects:
 
+	Note: Internal table elements,
+	which do not include table captions,
+	are excluded,
+	because the table layout algorithm
+	does not allow elements to become smaller than their inflow content.
+	Sizing a table cell as if it was empty and then layout out its content inside without changing the size
+	is effectively an undefined operation.
+	Manually setting the 'width' or 'height' properties to ''0''
+	cannot make it smaller than its content.
+	This concern does not apply to table captions,
+	which are perfectly capable of having a fixed size
+	that is independent of their content.
+
 	1. When calculating the size of the containing element,
 		it must be treated as having no contents.
 

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

@@ -109,6 +109,15 @@ <h1>CSS Contain Level 1 Disposition of Comments for 2018-05-24 CR</h1>
 Response: <a href='https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-413883793'>https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-413883793</a>
 Closed:   Accepted
 Resolved: <a href='https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-417016569'>https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-417016569</a></pre>
+<pre class='a' id='issue-10'>
+Issue 10. <a href='#issue-10'>#</a>
+Summary:  maybe 'contain-size' shouldn't apply to display:table-caption
+From:     David Baron
+Comment:  <a href='https://github.com/w3c/csswg-drafts/issues/2952'>https://github.com/w3c/csswg-drafts/issues/2952</a>
+Response: <a href='https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-408369314'>https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-408369314</a>
+Closed:   Rejected
+Resolved: <a href='https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325'>https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325</a>
+Verified: <a href='https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325'>https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325</a></pre>
 <script>
 (function () {
     var sheet = document.styleSheets[0];

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

@@ -79,3 +79,12 @@ Comment:  https://github.com/w3c/csswg-drafts/issues/3032
 Response: https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-413883793
 Closed:   Accepted
 Resolved: https://github.com/w3c/csswg-drafts/issues/3023#issuecomment-417016569
+----
+Issue 10.
+Summary:  maybe 'contain-size' shouldn't apply to display:table-caption
+From:     David Baron
+Comment:  https://github.com/w3c/csswg-drafts/issues/2952
+Response: https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-408369314
+Closed:   Rejected
+Resolved: https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325
+Verified: https://github.com/w3c/csswg-drafts/issues/2952#issuecomment-417018325