[css3-text] Implement text-decoration property shorthand

LayoutTests/inspector/styles/styles-computed-trace-expected.txt

Index: LayoutTests/inspector/styles/styles-computed-trace-expected.txt
diff --git a/LayoutTests/inspector/styles/styles-computed-trace-expected.txt b/LayoutTests/inspector/styles/styles-computed-trace-expected.txt
index bbb39841adfa1a448ed9c24e58d2fd6c928faeb1..344eff83102d16c49a43ec69b0ee22dbe0a493d3 100644
--- a/LayoutTests/inspector/styles/styles-computed-trace-expected.txt
+++ b/LayoutTests/inspector/styles/styles-computed-trace-expected.txt
@@ -25,8 +25,14 @@ font-family: Courier;
     #id1 - Courier styles-computed-trace.html:18
     /-- overloaded --/ #id1 - Times styles-computed-trace.html:13
     /-- overloaded --/ body - Arial styles-computed-trace.html:4
-text-decoration: underline;
+text-decoration: underline solid rgb(0, 0, 0);
     div - underline styles-computed-trace.html:9
+text-decoration-color: rgb(0, 0, 0);
+    div - initial styles-computed-trace.html:9
+text-decoration-line: underline;
+    div - underline styles-computed-trace.html:9
+text-decoration-style: solid;
+    div - initial styles-computed-trace.html:9
 
 [expanded] 
 element.style  { ()
@@ -43,9 +49,15 @@ font-family: Courier;
     /-- overloaded --/ #id1 - Courier styles-computed-trace.html:18
     /-- overloaded --/ #id1 - Times styles-computed-trace.html:13
     /-- overloaded --/ body - Arial styles-computed-trace.html:4
-text-decoration: underline;
+text-decoration: underline solid rgb(0, 0, 0);
     /-- overloaded --/ #id2 - invalidvalue styles-computed-trace.html:27
     div - underline styles-computed-trace.html:9
+text-decoration-color: rgb(0, 0, 0);
+    div - initial styles-computed-trace.html:9
+text-decoration-line: underline;
+    div - underline styles-computed-trace.html:9
+text-decoration-style: solid;
+    div - initial styles-computed-trace.html:9
 
 [expanded] 
 element.style  { ()