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

Source/core/css/parser/CSSPropertyParser.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 3775 matching lines @@
     }
 
     if (!rowCount || !columnCount)
         return nullptr;
 
     return CSSGridTemplateAreasValue::create(gridAreaMap, rowCount, columnCount);
 }
 
 PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseGridAutoFlow(CSSParserValueList& list)
 {
-    // [ row | column ] && dense? | stack && [ row | column ]?
+    // [ row | column ] || dense
     ASSERT(RuntimeEnabledFeatures::cssGridLayoutEnabled());
 
     CSSParserValue* value = list.current();
     if (!value)
         return nullptr;
 
     RefPtrWillBeRawPtr<CSSValueList> parsedValues = CSSValueList::createSpaceSeparated();
 
     // 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;
         default:
             return parsedValues;
         }
         parsedValues->append(cssValuePool().createIdentifierValue(value->id));
         list.next();
     }
 
@@ skipping 4735 matching lines @@
         }
     }
 
     if (!list->length())
         return nullptr;
 
     return list.release();
 }
 
 } // namespace blink