[CSS Shapes] Add parsing support for gradients

LayoutTests/fast/shapes/parsing/parsing-test-utils.js

 // Valid values for both shape-inside and shape-outside. Two values are specified when the shape property value
 // differs from the specified value. Three values are specified when the computed shape property value differs
 // from the specified value.
 // eg: "specified value/CSS Text value/computed style value"
 // or: ["specified value", "CSS Text value/computed style value"]
 // or: ["specified value", "CSS Text value", "Computed style value"]
 var validShapeValues = [
     "none",
 
     "inset(10px)",
@@ skipping 75 matching lines @@
     "margin-box",
 
     ["polygon(nonzero, 10px 10px, 20px 20px, 30px 30px) content-box", "polygon(10px 10px, 20px 20px, 30px 30px) content-box"],
     ["polygon(nonzero, 10px 10px, 20px 20px, 30px 30px) padding-box", "polygon(10px 10px, 20px 20px, 30px 30px) padding-box"],
     ["polygon(nonzero, 10px 10px, 20px 20px, 30px 30px) border-box",  "polygon(10px 10px, 20px 20px, 30px 30px) border-box"],
     ["polygon(nonzero, 10px 10px, 20px 20px, 30px 30px) margin-box",  "polygon(10px 10px, 20px 20px, 30px 30px) margin-box"],
 
     ["content-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)", "content-box polygon(10px 10px, 20px 20px, 30px 30px)", "polygon(10px 10px, 20px 20px, 30px 30px) content-box"],
     ["padding-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)", "padding-box polygon(10px 10px, 20px 20px, 30px 30px)", "polygon(10px 10px, 20px 20px, 30px 30px) padding-box"],
     ["border-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)", "border-box polygon(10px 10px, 20px 20px, 30px 30px)", "polygon(10px 10px, 20px 20px, 30px 30px) border-box"],
-    ["margin-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)", "margin-box polygon(10px 10px, 20px 20px, 30px 30px)", "polygon(10px 10px, 20px 20px, 30px 30px) margin-box"]
+    ["margin-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)", "margin-box polygon(10px 10px, 20px 20px, 30px 30px)", "polygon(10px 10px, 20px 20px, 30px 30px) margin-box"],
+
+     "linear-gradient(to right, red, blue)",
+     "radial-gradient(at 10px 20px, red 0%, blue 50%, green 95%)"
 ];
 
 // Invalid values for both shape-inside and shape-outside. When an invalid shape value is specified, the
 // shape property's computed value is the same as its default.
 var invalidShapeValues = [
     "calc()",
     "auto",
 
     "inset()",
     "inset(10px, 10px)",
@@ skipping 157 matching lines @@
 
 function testNotInheritedShapeProperty(property, parentValue, childValue, expectedValue)
 {
     shouldBeEqualToString('getParentAndChildComputedStylesString("' + property + '", "' + parentValue + '", "' + childValue + '")', expectedValue);
 }
 
 function applyToEachArglist(testFunction, arglists)
 {
     arglists.forEach(function(arglist, i, a) {testFunction.apply(null, arglist);});
 }