[css3-text] Implement text-decoration property shorthand

Source/core/css/CSSParser-in.cpp

Index: Source/core/css/CSSParser-in.cpp
diff --git a/Source/core/css/CSSParser-in.cpp b/Source/core/css/CSSParser-in.cpp
index 34dd18efbdea92296545d9998f2df73fd9c40c57..0895dd7bcfc1d14a0225a75a043f524e6766a2df 100644
--- a/Source/core/css/CSSParser-in.cpp
+++ b/Source/core/css/CSSParser-in.cpp
@@ -2118,6 +2118,11 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     }
 
     case CSSPropertyTextDecoration:
+        // Fall through to CSS2.1 implementation if runtime feature is disabled.
+        if (RuntimeEnabledFeatures::css3TextDecorationsEnabled()) {
+            // [ <text-decoration-line> || <text-decoration-style> || <text-decoration-color> ] | inherit
+            return parseShorthand(CSSPropertyTextDecoration, textDecorationShorthand(), important);
+        }
     case CSSPropertyWebkitTextDecorationsInEffect:
     case CSSPropertyTextDecorationLine:
         // none | [ underline || overline || line-through || blink ] | inherit
@@ -8813,7 +8818,8 @@ bool CSSParser::parseTextDecoration(CSSPropertyID propId, bool important)
             value = m_valueList->next();
     }
 
-    if (list->length() && isValid) {
+    // Values are either valid or in shorthand scope.
+    if (list->length() && (isValid || inShorthand())) {

[Julien - ping for review, 2013/07/27 01:46:35]

Is it totally right to allow an empty list of keywords to be considered fine
here? (e.g. navy dotted row)

[abinader, 2013/07/28 04:21:52]

If I understood your question correctly, you are questioning whether doing the
following:

elem.style.textDecoration = "navy dotted"

Would be valid. So the answer is yes: according to the specification, "Omitted
values are set to their initial values." - in this case, the text decoration
line value is omitted, thus making it revert back to "initial", which is then
properly computed as "none". I'll add it to the
getComputedStyle-text-decoration-shorthand.html layout test for sanity check.

[Julien - ping for review, 2013/07/29 18:53:11]

Ah, that's not really what I meant (sorry for being unclear). Rereading the
logic, it's actually OK anyway: I was afraid we would accept non-valid
text-decoration-style values here due to the inShorthand() check.

[abinader, 2013/07/29 21:15:32]

Ah, I see your point now :) no, this function is not responsible for
text-decoration-style.

         addTextDecorationProperty(propId, list.release(), important);
         return true;
     }