Correct content-box fixed table sizing

render-repros/checks.json

@@ -276,7 +276,9 @@
     {"name": "separate model charges outer spacing before first track", "color": "#862e9c", "x": 14, "y": 104, "width": 50, "height": 30},
     {"name": "separate model removes border and all spacing from track space", "color": "#15aabf", "x": 74, "y": 104, "width": 212, "height": 30},
     {"name": "later separate row cannot resize first track", "color": "#c2255c", "x": 14, "y": 134, "width": 50, "height": 30},
-    {"name": "later separate row preserves remaining track", "color": "#fab005", "x": 74, "y": 134, "width": 212, "height": 30}
+    {"name": "later separate row preserves remaining track", "color": "#fab005", "x": 74, "y": 134, "width": 212, "height": 30},
+    {"name": "content-box table keeps spacing inside declared width", "color": "#5f3dc4", "x": 14, "y": 212, "width": 50, "height": 30},
+    {"name": "content-box remaining track excludes borders and spacing", "color": "#66a80f", "x": 74, "y": 212, "width": 220, "height": 30}
   ],
   "table-row-geometry": [
     {"name": "cell height remains a minimum below block content", "color": "#1971c2", "x": 0, "y": 0, "width": 40, "height": 30},

render-repros/fixed-table-layout.html

@@ -6,6 +6,7 @@
   td { height: 30px; padding: 0; border: 0 }
   .collapsed { border-collapse: collapse }
   .separate { margin-top: 40px; border: 4px solid #212529; border-spacing: 10px 0 }
+  .content-box { box-sizing: content-box }
   .first { width: 50px }
   .long { color: transparent; white-space: nowrap }
 </style>
@@ -17,3 +18,6 @@
   <tr><td class="first" style="background:#862e9c"></td><td style="background:#15aabf"></td></tr>
   <tr><td class="long" style="background:#c2255c">XXXXXXXXXXXXXXXXXXXXXXXX</td><td style="background:#fab005"></td></tr>
 </table>
+<table class="separate content-box">
+  <tr><td class="first" style="background:#5f3dc4"></td><td style="background:#66a80f"></td></tr>
+</table>