[CSS Grid Layout] the "grid-template-areas" is not identified as computable property.

LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt

Index: LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt
diff --git a/LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt b/LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt
index 344eff83102d16c49a43ec69b0ee22dbe0a493d3..9b3f3d054a315075522305d2a1105965c3ae76ae 100644
--- a/LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt
+++ b/LayoutTests/inspector/elements/styles/styles-computed-trace-expected.txt
@@ -72,4 +72,26 @@ button[Attributes Style]  { ()
 display: none;
 
 
+==== Style for ID4 (Grid Layout properties ====
+[expanded] 
+display: grid;
+    #id4 - grid styles-computed-trace.html:33
+    /-- overloaded --/ div - block user agent stylesheet
+font-family: Arial;
+    body - Arial styles-computed-trace.html:4
+grid-template-areas: "a";
+    #id4 - "a" styles-computed-trace.html:33
+text-decoration: underline solid rgb(0, 0, 0);
+    div - underline styles-computed-trace.html:9
+text-decoration-color: rgb(0, 0, 0);
+    div - initial styles-computed-trace.html:9
+text-decoration-line: underline;
+    div - underline styles-computed-trace.html:9
+text-decoration-style: solid;
+    div - initial styles-computed-trace.html:9
+
+[expanded] 
+element.style  { ()
+
+