[css-sizing] Remove repudiate-floats and contain-floats, since we have display:flow-root now to do it properly.

Author: tabatkins

css-sizing/Overview.bs

@@ -262,22 +262,14 @@ New Keywords for 'width' and 'height'</h3>
 		<dd>
 			Use the <a>fit-content inline size</a> or <a>fit-content block size</a>,
 			as appropriate to the writing mode.
-
-		<dt><dfn>repudiate-floats</dfn> <span class='issue'>Less stupid name?</span>
-		<dd>
-			In the <a>inline axis</a>,
-			use the larger of the <a>min-content inline size</a>,
-			and the <a>fill-available inline size</a> minus the size of any non-descendant floats in the same formatting context.
-			(This is similar to the behavior of a box that establishes a formatting context next to a float.)
-			In the <a>block axis</a>,
-			this is identical to ''width/auto''.
-
-			<p class='issue'>
-				Does this value work?
-				Is it needed?
-				<a href="http://lists.w3.org/Archives/Public/www-style/2013Feb/0212.html">Feedback from dbaron</a>
 	</dl>
 
+	Note: To size an element such that it avoids overlapping sibling floats,
+	make sure it's a <a>formatting context</a>.
+	For some layout modes, such as Grid and Flexbox,
+	this is true automatically.
+	For Block layout, this means using ''display: flow-root;''.
+
 	<p class="issue">
 		Right now all of these except ''width/fill'' mean the same thing
 		for block-sizes. This may or may not be ideal.
@@ -289,27 +281,18 @@ New Keywords for 'width' and 'height'</h3>
 
 	<p class='note'>
 		Note that percentages resolved against the intrinsic sizes
-		(''width/max-content'', ''width/min-content'', ''width/fit-content'', ''width/repudiate-floats'')
+		(''width/max-content'', ''width/min-content'', ''width/fit-content'')
 		will compute to ''width/auto'',
 		<a href="http://www.w3.org/TR/CSS21/visudet.html#the-height-property">as defined by CSS 2.1</a>. [[!CSS21]]
 
 <h3 id='the-contain-floats-value'>
 Containing Floats</h3>
 
-	<pre class="propdef partial">
-	Name: min-width, min-height
-	New values: contain-floats
-	</pre>
-
-	<dl>
-		<dt><dfn for="min-width, min-height" value>contain-floats</dfn>
-		<dd>
-			Equivalent to ''min-width/min-content''
-			except that when applied to the block-size of a block box
-			it forces the inner block-size to be large enough to contain
-			the margin boxes of any floats that originate inside the block
-			and that participate in the same block formatting context as the block's immediate contents.
-	</dl>
+	Note: To ensure that a container sizes itself to contain any descendant floats,
+	make sure it's a <a>formatting context</a>.
+	For some layout modes, such as Grid and Flexbox,
+	this is true automatically.
+	For Block layout, this means using ''display: flow-root;''.
 
 <h3 id='column-sizing'>
 Column Sizing Keywords</h3>