[CSS Grid Layout] Remove stack from grid-auto-flow syntax

Source/core/css/parser/CSSPropertyParser.cpp

Index: Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/Source/core/css/parser/CSSPropertyParser.cpp b/Source/core/css/parser/CSSPropertyParser.cpp
index 3e50cab7bcf86ea4fc864aea921a173b5e2021de..edf98afef14c295ef460653faf268ef0e564f716 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -3793,7 +3793,7 @@ PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseGridTemplateAreas()
 
 PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseGridAutoFlow(CSSParserValueList& list)
 {
-    // [ row | column ] && dense? | stack && [ row | column ]?
+    // [ row | column ] || dense
     ASSERT(RuntimeEnabledFeatures::cssGridLayoutEnabled());
 
     CSSParserValue* value = list.current();
@@ -3804,24 +3804,20 @@ PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseGridAutoFlow(CSSParserV
 
     // First parameter.
     CSSValueID firstId = value->id;
-    if (firstId != CSSValueRow && firstId != CSSValueColumn && firstId != CSSValueDense && firstId != CSSValueStack)
+    if (firstId != CSSValueRow && firstId != CSSValueColumn && firstId != CSSValueDense)
         return nullptr;
     parsedValues->append(cssValuePool().createIdentifierValue(firstId));
 
     // Second parameter, if any.
     value = list.next();
-    if (!value && firstId == CSSValueDense)
-        return nullptr;
-
     if (value) {
         switch (firstId) {

[Julien - ping for review, 2015/01/05 13:11:34]

We could probably simplify this code now that we basically have 2 real cases to
handle (row or column with and without dense).

[Manuel Rego, 2015/01/08 12:50:28]

I don't see very clear how to simplify this code.

Maybe you're missing that we could have "row dense" and "dense row",
so we need to check both parameters depending on the other.

[Julien - ping for review, 2015/01/09 09:13:03]

OK!

         case CSSValueRow:
         case CSSValueColumn:
-            if (value->id != CSSValueDense && value->id != CSSValueStack)
+            if (value->id != CSSValueDense)
                 return parsedValues;
             break;
         case CSSValueDense:
-        case CSSValueStack:
             if (value->id != CSSValueRow && value->id != CSSValueColumn)
                 return parsedValues;
             break;