[CSS Grid Layout] Rename grid-definition-{columns|rows} to match the new syntax

Source/devtools/front_end/CSSMetadata.js

 /*
  * Copyright (C) 2010 Nikita Vasilyev. All rights reserved.
  * Copyright (C) 2010 Joseph Pecoraro. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 643 matching lines @@
     "background-repeat-y": { m: "background" },
     "border-top": { m: "background" },
     "border-right": { m: "background" },
     "border-bottom": { m: "background" },
     "border-left": { m: "background" },
     "border-radius": { m: "background" },
     "bottom": { m: "visuren" },
     "color": { m: "color", a: "foreground" },
     "counter-increment": { m: "generate" },
     "counter-reset": { m: "generate" },
-    "grid-definition-columns": { m: "grid" },
-    "grid-definition-rows": { m: "grid" },
+    "grid-template-columns": { m: "grid" },
+    "grid-template-rows": { m: "grid" },
     "height": { m: "box" },
     "image-orientation": { m: "images" },
     "left": { m: "visuren" },
     "list-style": { m: "lists" },
     "min-height": { m: "box" },
     "min-width": { m: "box" },
     "opacity": { m: "color", a: "transparency" },
     "orphans": { m: "page" },
     "outline-offset": { m: "ui" },
     "padding": { m: "box", a: "padding1" },
@@ skipping 315 matching lines @@
 
     /**
      * @param {string} longhand
      * @return {?Array.<string>}
      */
     shorthands: function(longhand)
     {
         return this._shorthands[longhand];
     }
 }