[CSS Grid Layout] Flex tracks sizing alg must handle 0fr values

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

 description('Test that setting and getting grid-template-columns and grid-template-rows works as expected');
 
 debug("Test getting grid-template-columns and grid-template-rows set through CSS");
 testGridDefinitionsValues(document.getElementById("gridWithNoneElement"), "none", "none");
 testGridDefinitionsValues(document.getElementById("gridWithFixedElement"), "10px", "15px");
 testGridDefinitionsValues(document.getElementById("gridWithPercentElement"), "53%", "27%");
 testGridDefinitionsValues(document.getElementById("gridWithAutoElement"), "auto", "auto");
 testGridDefinitionsValues(document.getElementById("gridWithEMElement"), "100px", "150px");
 testGridDefinitionsValues(document.getElementById("gridWithViewPortPercentageElement"), "64px", "60px");
 testGridDefinitionsValues(document.getElementById("gridWithMinMax"), "minmax(10%, 15px)", "minmax(20px, 50%)");
@@ skipping 38 matching lines @@
 testNonGridDefinitionsSetJSValues("minmax(min-content, 8vh)", "minmax(10vw, min-content)", "minmax(min-content, 48px)", "minmax(80px, min-content)");
 testNonGridDefinitionsSetJSValues("minmax(22em, max-content)", "minmax(max-content, 5em)", "minmax(220px, max-content)", "minmax(max-content, 50px)");
 testNonGridDefinitionsSetJSValues("minmax(min-content, max-content)", "minmax(max-content, min-content)");
 // Unit comparison should be case-insensitive.
 testNonGridDefinitionsSetJSValues("3600Fr", "154fR", "3600fr", "154fr", "3600fr", "154fr");
 // Float values are allowed.
 testNonGridDefinitionsSetJSValues("3.1459fr", "2.718fr");
 // A leading '+' is allowed.
 testNonGridDefinitionsSetJSValues("+3fr", "+4fr", "3fr", "4fr", "3fr", "4fr");
 testNonGridDefinitionsSetJSValues("minmax(auto, 8vh)", "minmax(10vw, auto)", "minmax(auto, 48px)", "minmax(80px, auto)");
+// Flex factor values can be zero.
+testGridDefinitionsSetJSValues("0fr", ".0fr", "0px", "0px", "0fr", "0fr");
+testGridDefinitionsSetJSValues("minmax(0fr, 0fr)", "minmax(.0fr, .0fr)", "0px", "0px", "minmax(0fr, 0fr)", "minmax(0fr, 0fr)");
 
 debug("");
 debug("Test setting grid-template-columns and grid-template-rows to bad values through JS");
 // No comma and only 1 argument provided.
 testGridDefinitionsSetBadJSValues("minmax(10px 20px)", "minmax(10px)")
 // Nested minmax and only 2 arguments are allowed.
 testGridDefinitionsSetBadJSValues("minmax(minmax(10px, 20px), 20px)", "minmax(10px, 20px, 30px)");
 // No breadth value and no comma.
 testGridDefinitionsSetBadJSValues("minmax()", "minmax(30px 30% 30em)");
 testGridDefinitionsSetBadJSValues("-2fr", "3ffr");
 testGridDefinitionsSetBadJSValues("-2.05fr", "+-3fr");
-testGridDefinitionsSetBadJSValues("0fr", "1r");
+testGridDefinitionsSetBadJSValues("1f", "1r");
 // A dimension doesn't allow spaces between the number and the unit.
-testGridDefinitionsSetBadJSValues(".0000fr", "13 fr");
+testGridDefinitionsSetBadJSValues(".0001 fr", "13 fr");
 testGridDefinitionsSetBadJSValues("7.-fr", "-8,0fr");
 // Negative values are not allowed.
 testGridDefinitionsSetBadJSValues("-1px", "-6em");
 testGridDefinitionsSetBadJSValues("minmax(-1%, 32%)", "minmax(2vw, -6em)");
 
 debug("");
 debug("Test setting grid-template-columns and grid-template-rows back to 'none' through JS");
 testNonGridDefinitionsSetJSValues("18px", "66px");
 testNonGridDefinitionsSetJSValues("none", "none");
 
@@ skipping 29 matching lines @@
     element.style.gridTemplateColumns = "initial";
     element.style.gridTemplateRows = "initial";
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-template-columns')", "'none'");
     shouldBe("getComputedStyle(element, '').getPropertyValue('grid-template-rows')", "'none'");
 
     document.body.removeChild(element);
 }
 debug("");
 debug("Test setting grid-template-columns and grid-template-rows to 'initial' through JS");
 testInitial();