[css-tables] Change table-cell-child percentage-resolution based on Chrome compat issues

Author: FremyCompany

css-tables-3/Overview.bs

@@ -34,6 +34,7 @@ spec:css22; type:property; text:overflow
 spec:css22; type:property; text:white-space
 spec:css22; type:property; text:display
 spec:filter-effects-1; type:property; text:filter
+spec:css-sizing-3; type:property; text:box-sizing
 </pre>
 
 <!--
@@ -1908,10 +1909,77 @@ spec:filter-effects-1; type:property; text:filter
 					if the cell is considered to have its height specified explicitly
 					or the child is absolutely positioned, see <a href="http://www.w3.org/TR/CSS2/visudet.html#the-height-property">CSS 2</a>.
 
-				It is further clarified that
+				For compat reasons, it is further clarified that
 					a cell is considered to have its height specified explicitly
-					if the computed height of the cell or any of its table ancestors is a length or percentage,
-					and that percentage does not <a>behave as auto</a>.
+					if the computed height of the cell is a length, or 
+					if the computed height of its table-root ancestor is a length or percentage,
+					regardless of whether that percentage does <a>behave as auto</a> or not.
+
+			</div>
+
+			<div class="example">
+				To clarify the preceding statements, here is a table of the resulting "A" div height based on the value being used:
+				<xmp>
+					<section style="height: var(--wrapper-height)">
+						<table style="height: var(--table-height)">
+							<tr>
+								<td style="height: var(--table-cell-height)">
+
+									<div style="height:100%; background:yellow">A</div>
+
+								</td>
+								<td style="height: var(--other-table-cell-height)">
+
+									B<br>C
+
+								</td>
+							</tr>
+						</table>
+					</section>
+				</xmp>
+
+				<table border="1" rules="all" style="margin: auto; font-family: 'Consolas', monospace">
+					<thead>
+						<tr>
+							<th>--table-cell-height&nbsp;&nbsp;</th>
+							<th>--table-height&nbsp;&nbsp;</th>
+							<th>result&nbsp;&nbsp;</th>
+						</tr>
+					</thead>
+					
+					<tbody>
+						<tr>
+							<td>&lt;length&gt;</td>
+							<td><i style="opacity:0.5">&lt;any&gt;</i></td>
+							<td><img src="images/percentage-heights-hundred-percent.png" width="23" height="29" style="vertical-align: middle" alt="100%" title="Percentage honored during second layout pass"></td>
+						</tr>
+						<tr>
+							<td><i style="opacity:0.5">&lt;any&gt;</i></td>
+							<td>&lt;length&gt;</td>
+							<td><img src="images/percentage-heights-hundred-percent.png" width="23" height="29" style="vertical-align: middle" alt="100%" title="Percentage honored during second layout pass"></td>
+						</tr>
+						<tr>
+							<td><i style="opacity:0.5">&lt;any&gt;</i></td>
+							<td>&lt;percentage&gt;</td>
+							<td><img src="images/percentage-heights-hundred-percent.png" width="23" height="29" style="vertical-align: middle" alt="100%" title="Percentage honored during second layout pass"></td>
+						</tr>
+						<tr>
+							<td>auto</td>
+							<td>auto</td>
+							<td><img src="images/percentage-heights-auto.png" width="23" height="29" style="vertical-align: middle" alt="auto" title="Percentage ignored; no second layout pass"></td>
+						</tr>
+						<tr>
+							<td>&lt;percentage&gt;</td>
+							<td>auto</td>
+							<td><img src="images/percentage-heights-auto.png" width="23" height="29" style="vertical-align: middle" alt="auto" title="Percentage ignored; no second layout pass"></td>
+						</tr>
+					</tbody>
+				</table>
+
+				Note that neither <code>--other-table-cell-height</code> nor <code>--wrapper-height</code> do influence the algorithm's outcome.
+
+				A previous version of this specification incorrectly stated that <code>--wrapper-height</code> was taken into account when the table had a percentage height, 
+				but compat issues appeared when an implementation landed, and the behavior was then special-cased.
 
 			</div>