[CSS Grid Layout] Update named grid lines syntax to the last version of the specs

LayoutTests/fast/css-grid-layout/resources/grid-columns-rows-get-set.js

 description('Test that setting and getting grid-definition-columns and grid-definition-rows works as expected');
 
 debug("Test getting grid-definition-columns and grid-definition-rows set through CSS");
 testGridDefinitionsValues(document.getElementById("gridWithNoneElement"), "none", "none");
 testGridDefinitionsValues(document.getElementById("gridWithFixedElement"), "10px", "15px");
 testGridDefinitionsValues(document.getElementById("gridWithPercentElement"), "400px", "150px");
 testGridDefinitionsValues(document.getElementById("gridWithAutoElement"), "0px", "0px");
 testGridDefinitionsValues(document.getElementById("gridWithAutoWithoutSizeElement"), "0px", "0px");
 testGridDefinitionsValues(document.getElementById("gridWithAutoWithChildrenElement"), "7px", "11px");
 testGridDefinitionsValues(document.getElementById("gridWithEMElement"), "100px", "150px");
@@ skipping 66 matching lines @@
 
 debug("");
 debug("Test setting grid-definition-columns and grid-definition-rows back to 'none' through JS");
 testGridDefinitionsSetJSValues("18px", "66px");
 testGridDefinitionsSetJSValues("none", "none");
 
 function testInherit()
 {
     var parentElement = document.createElement("div");
     document.body.appendChild(parentElement);
-    parentElement.style.gridDefinitionColumns = "50px 'last'";
-    parentElement.style.gridDefinitionRows = "'first' 101%";
+    parentElement.style.gridDefinitionColumns = "50px (last)";
+    parentElement.style.gridDefinitionRows = "(first) 101%";
 
     element = document.createElement("div");
     parentElement.appendChild(element);
     element.style.display = "grid";
     element.style.height = "100px";
     element.style.gridDefinitionColumns = "inherit";
     element.style.gridDefinitionRows = "inherit";
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-columns')", "'50px last'");
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-rows')", "'first 101px'");
 
     document.body.removeChild(parentElement);
 }
 debug("");
 debug("Test setting grid-definition-columns and grid-definition-rows to 'inherit' through JS");
 testInherit();
 
 function testInitial()
 {
     element = document.createElement("div");
     document.body.appendChild(element);
     element.style.display = "grid";
     element.style.width = "300px";
     element.style.height = "150px";
-    element.style.gridDefinitionColumns = "150% 'last'";
-    element.style.gridDefinitionRows = "'first' 1fr";
+    element.style.gridDefinitionColumns = "150% (last)";
+    element.style.gridDefinitionRows = "(first) 1fr";
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-columns')", "'450px last'");
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-rows')", "'first 150px'");
 
     element.style.display = "grid";
     element.style.gridDefinitionColumns = "initial";
     element.style.gridDefinitionRows = "initial";
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-columns')", "'none'");
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-definition-rows')", "'none'");
 
     document.body.removeChild(element);
 }
 debug("");
 debug("Test setting grid-definition-columns and grid-definition-rows to 'initial' through JS");
 testInitial();