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

Source/core/css/resolver/StyleBuilderConverter.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 316 matching lines @@
 GridAutoFlow StyleBuilderConverter::convertGridAutoFlow(StyleResolverState&, CSSValue* value)
 {
     CSSValueList* list = toCSSValueList(value);
 
     ASSERT(list->length() >= 1);
     CSSPrimitiveValue* first = toCSSPrimitiveValue(list->item(0));
     CSSPrimitiveValue* second = list->length() == 2 ? toCSSPrimitiveValue(list->item(1)) : nullptr;
 
     switch (first->getValueID()) {
     case CSSValueRow:
-        if (second) {
-            if (second->getValueID() == CSSValueDense)
-                return AutoFlowRowDense;
-            return AutoFlowStackRow;
-        }
+        if (second && second->getValueID() == CSSValueDense)
+            return AutoFlowRowDense;
         return AutoFlowRow;
     case CSSValueColumn:
-        if (second) {
-            if (second->getValueID() == CSSValueDense)
-                return AutoFlowColumnDense;
-            return AutoFlowStackColumn;
-        }
+        if (second && second->getValueID() == CSSValueDense)
+            return AutoFlowColumnDense;
         return AutoFlowColumn;
     case CSSValueDense:
         if (second && second->getValueID() == CSSValueColumn)
             return AutoFlowColumnDense;
         return AutoFlowRowDense;
-    case CSSValueStack:
-        if (second && second->getValueID() == CSSValueColumn)
-            return AutoFlowStackColumn;
-        return AutoFlowStackRow;
     default:
         ASSERT_NOT_REACHED();
         return RenderStyle::initialGridAutoFlow();
     }
 }
 
 GridPosition StyleBuilderConverter::convertGridPosition(StyleResolverState&, CSSValue* value)
 {
     // We accept the specification's grammar:
     // 'auto' | [ <integer> || <custom-ident> ] | [ span && [ <integer> || <custom-ident> ] ] | <custom-ident>
@@ skipping 482 matching lines @@
     CSSPrimitiveValue* primitiveValueZ = toCSSPrimitiveValue(list->item(2));
 
     return TransformOrigin(
         convertOriginLength<CSSValueLeft, CSSValueRight>(state, primitiveValueX),
         convertOriginLength<CSSValueTop, CSSValueBottom>(state, primitiveValueY),
         StyleBuilderConverter::convertComputedLength<float>(state, primitiveValueZ)
     );
 }
 
 } // namespace blink