[css-flexbox] Fix dholbert's issue with items that'll get clamped past their base size causing bad free space calculations.

--HG--
extra : rebase_source : 5c8149f49a7c1a90f7a9e716daddfdd0c5239fef

Author: tabatkins

css-flexbox/Overview.bs

@@ -2333,6 +2333,13 @@ Resolving Flexible Lengths</h3>
 			for all other items,
 			both flexible and inflexible,
 			use their outer <a>flex base size</a>.
+			If the <i>flex grow factor</i> is being used for this algorithm,
+			clamp the items’ <a>flex base size</a>
+			by their max main size;
+			if the <i>flex shrink factor</i> is being used for this algorithm,
+			clamp the items’ <a>flex base size</a>
+			by the min main size.
+
 			Subtract this sum from the flex container's inner main size.
 			This is the free space.
 

css-flexbox/Overview.html

@@ -2360,8 +2360,15 @@ <h3 class="heading settled heading" data-level=9.7 id=resolve-flexible-lengths><
 			for all other items,
 			both flexible and inflexible,
 			use their outer <a data-link-type=dfn href=#flex-base-size title="flex base size">flex base size</a>.
-			Subtract this sum from the flex container’s inner main size.
-			This is the free space.
+			If the <a data-link-type=dfn href=#flex-grow-factor title="flex grow factor">flex grow factor</a> is being used for this algorithm,
+			clamp the items’ <a data-link-type=dfn href=#flex-base-size title="flex base size">flex base size</a>
+			by their max main size;
+			if the <a data-link-type=dfn href=#flex-shrink-factor title="flex shrink factor">flex shrink factor</a> is being used for this algorithm,
+			clamp the items’ <a data-link-type=dfn href=#flex-base-size title="flex base size">flex base size</a>
+			by the min main size.
+
+<p>Subtract this sum from the flex container’s inner main size.
+			This is the free space.</p>
 
 		<li>
 			<strong>Calculate desired free space.</strong>