DevTools: Add valid "border-style" property values to CSSMetadata

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 234 matching lines @@
     "cursor": { values: [
         "none", "copy", "auto", "crosshair", "default", "pointer", "move", "vertical-text", "cell", "context-menu",
         "alias", "progress", "no-drop", "not-allowed", "-webkit-zoom-in", "-webkit-zoom-out", "e-resize", "ne-resize",
         "nw-resize", "n-resize", "se-resize", "sw-resize", "s-resize", "w-resize", "ew-resize", "ns-resize",
         "nesw-resize", "nwse-resize", "col-resize", "row-resize", "text", "wait", "help", "all-scroll", "-webkit-grab",
         "-webkit-grabbing"
     ] },
     "border-width": { values: [
         "medium", "thick", "thin"
     ] },
+    "border-style": { values: [
+        "none", "hidden", "inset", "groove", "ridge", "outset", "dotted", "dashed", "solid", "double"
+    ] },
     "size": { values: [
         "a3", "a4", "a5", "b4", "b5", "landscape", "ledger", "legal", "letter", "portrait"
     ] },
     "background-size": { values: [
         "contain", "cover"
     ] },
     "direction": { values: [
         "ltr", "rtl"
     ] },
     "marquee-direction": { values: [
@@ skipping 724 matching lines @@
      * @param {string} longhand
      * @return {?Array.<string>}
      */
     shorthands: function(longhand)
     {
         return this._shorthands[longhand];
     }
 }
 
 WebInspector.CSSMetadata.initializeWithSupportedProperties([]);