[CSS Shapes] Add parsing support for gradients

LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt

Index: LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt
diff --git a/LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt b/LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt
index 789587937e70daf6145ce63e2325dc192ee539df..8dc5fae554b2a8e656a59d8ab2f2c47b5d4c0f20 100644
--- a/LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt
+++ b/LayoutTests/fast/shapes/parsing/parsing-shape-outside-expected.txt
@@ -165,6 +165,10 @@ PASS getCSSText("shape-outside", "border-box polygon(nonzero, 10px 10px, 20px 20
 PASS getComputedStyleValue("shape-outside", "border-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)") is "polygon(10px 10px, 20px 20px, 30px 30px) border-box"
 PASS getCSSText("shape-outside", "margin-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)") is "margin-box polygon(10px 10px, 20px 20px, 30px 30px)"
 PASS getComputedStyleValue("shape-outside", "margin-box polygon(nonzero, 10px 10px, 20px 20px, 30px 30px)") is "polygon(10px 10px, 20px 20px, 30px 30px) margin-box"
+PASS getCSSText("shape-outside", "linear-gradient(to right, red, blue)") is "linear-gradient(to right, red, blue)"
+PASS getComputedStyleValue("shape-outside", "linear-gradient(to right, red, blue)") is "linear-gradient(to right, red, blue)"
+PASS getCSSText("shape-outside", "radial-gradient(at 10px 20px, red 0%, blue 50%, green 95%)") is "radial-gradient(at 10px 20px, red 0%, blue 50%, green 95%)"
+PASS getComputedStyleValue("shape-outside", "radial-gradient(at 10px 20px, red 0%, blue 50%, green 95%)") is "radial-gradient(at 10px 20px, red 0%, blue 50%, green 95%)"
 PASS removeBaseURL(getCSSText("shape-outside", "url('image')")) is "url(image)"
 PASS removeBaseURL(getComputedStyleValue("shape-outside", "url('image')")) is "url(image)"
 PASS getCSSText("shape-outside", "calc()") is ""