[css-grid] Try to handle baseline-aligned items whose height depends on the size of the track, by ignoring them. Related to #1365.

Author: tabatkins

css-grid-1/Overview.bs

@@ -3703,9 +3703,20 @@ Resolve Intrinsic Track Sizes</h3>
 			so that,
 			when start/end-aligned together
 			their [[css-align-3#baseline-values|baselines align as specified]].
+			An item whose size depends
+			on the size of the tracks they span in this axis
+			is ignored for the purpose of calculating such “shims”.
 
 			Consider these “shims” as part of the items’ intrinsic size contribution
 			for the purpose of track sizing, below.
+
+			<div class=example>
+				For example,
+				if several grid items with text and ''height: auto''
+				are baseline-aligned with an image with ''height: 100%'',
+				the image is ignored when calculating the shims that the other items will have.
+				(And the image itself will have no shim at all.)
+			</div>
 			</ins>
 
 		<li>