[css3-text] Implement text-decoration property shorthand

LayoutTests/svg/css/getComputedStyle-basic-expected.txt

Index: LayoutTests/svg/css/getComputedStyle-basic-expected.txt
diff --git a/LayoutTests/svg/css/getComputedStyle-basic-expected.txt b/LayoutTests/svg/css/getComputedStyle-basic-expected.txt
index 40fd0d4e861bb53a4997e959b9f509d2cecd96b3..19e76bde09c776ef617d21964a1d7cf0073d2162 100644
--- a/LayoutTests/svg/css/getComputedStyle-basic-expected.txt
+++ b/LayoutTests/svg/css/getComputedStyle-basic-expected.txt
@@ -166,8 +166,8 @@ rect: style.getPropertyValue(tab-size) : 8
 rect: style.getPropertyCSSValue(tab-size) : [object CSSPrimitiveValue]
 rect: style.getPropertyValue(text-align) : start
 rect: style.getPropertyCSSValue(text-align) : [object CSSPrimitiveValue]
-rect: style.getPropertyValue(text-decoration) : none
-rect: style.getPropertyCSSValue(text-decoration) : [object CSSPrimitiveValue]
+rect: style.getPropertyValue(text-decoration) : none solid rgb(0, 0, 0)
+rect: style.getPropertyCSSValue(text-decoration) : [object CSSValueList]
 rect: style.getPropertyValue(text-indent) : 0px
 rect: style.getPropertyCSSValue(text-indent) : [object CSSPrimitiveValue]
 rect: style.getPropertyValue(text-rendering) : auto
@@ -656,8 +656,8 @@ g: style.getPropertyValue(tab-size) : 8
 g: style.getPropertyCSSValue(tab-size) : [object CSSPrimitiveValue]
 g: style.getPropertyValue(text-align) : start
 g: style.getPropertyCSSValue(text-align) : [object CSSPrimitiveValue]
-g: style.getPropertyValue(text-decoration) : none
-g: style.getPropertyCSSValue(text-decoration) : [object CSSPrimitiveValue]
+g: style.getPropertyValue(text-decoration) : none solid rgb(0, 0, 0)
+g: style.getPropertyCSSValue(text-decoration) : [object CSSValueList]
 g: style.getPropertyValue(text-indent) : 0px
 g: style.getPropertyCSSValue(text-indent) : [object CSSPrimitiveValue]
 g: style.getPropertyValue(text-rendering) : auto