[css-flexbox] Require percentrage resolution to depend on the container being definite too.

Author: tabatkins

css-flexbox/Overview.bs

@@ -2742,7 +2742,8 @@ Definite and Indefinite Sizes</h3>
 		<li>
 			If a percentage is going to be resolved against a <a>flex item’s</a> <a>main size</a>,
 			and the <a>flex item</a> has a <a>definite</a> <a>flex basis</a>,
-			the <a>main size</a> must be treated as <a>definite</a>
+			and the <a>flex container</a> has a <a>definite</a> <a>main size</a>,
+			the <a>flex item’s</a> <a>main size</a> must be treated as <a>definite</a>
 			for the purpose of resolving the percentage,
 			and the percentage must resolve against the <strong>flexed</strong> <a>main size</a> of the <a>flex item</a>
 			(that is, after the layout algorithm below has been completed for the <a>flex item’s</a> <a>flex container</a>,
@@ -3277,7 +3278,7 @@ Clarifications</h4>
 			Restored normative status of note about table wrapper boxes normative;
 			it had been accidentally changed in the previous draft.
 			(Issue <a href="http://dev.w3.org/csswg/css-flexbox-1/issues-lc-20140925#issue-2">2</a>)
-            
+
 		<li id="change-201409-display-longhands">
 			Removed references to 'display' property longhands,
 			since they will be removed from CSS Display Level 3.