[css-align] Implement place-content alignment shorthand

third_party/WebKit/Source/core/css/CSSProperties.json5

 {
 // This file specifies all the CSS properties we support and the necessary
 // information for our code generation. The various supported arguments
 // are described below with example usage
 
   parameters: {
     // - alias_for: "other-property"
     // Properties specifying alias_for should be virtually identical to the
     // properties they alias. Minor parsing differences are allowed as long as
     // the CSSValues created are of the same format of the aliased property.
@@ skipping 2663 matching lines @@
     {
       name: "font-variant",
       longhands: "font-variant-ligatures;font-variant-caps;font-variant-numeric",
     },
     {
       name: "grid",
       longhands: "grid-template-rows;grid-template-columns;grid-template-areas;grid-auto-flow;grid-auto-rows;grid-auto-columns;grid-column-gap;grid-row-gap",
       runtime_flag: "CSSGridLayout",
     },
     {
+      name: "place-content",
+      longhands: "align-content;justify-content",
+      runtime_flag: "CSSGridLayout",
+    },
+    {
       name: "grid-area",
       longhands: "grid-row-start;grid-column-start;grid-row-end;grid-column-end",
       runtime_flag: "CSSGridLayout",
     },
     {
       name: "grid-column",
       longhands: "grid-column-start;grid-column-end",
       runtime_flag: "CSSGridLayout",
     },
     {
@@ skipping 397 matching lines @@
     {
       name: "-webkit-transition-timing-function",
       alias_for: "transition-timing-function",
     },
     {
       name: "-webkit-user-select",
       alias_for: "user-select",
     },
   ],
 }