Add support for parsing <grid-line> that includes a 'span'

Source/WebCore/css/StyleResolver.cpp

Index: Source/WebCore/css/StyleResolver.cpp
diff --git a/Source/WebCore/css/StyleResolver.cpp b/Source/WebCore/css/StyleResolver.cpp
index 8e2d8c45d8b813c537c7973119034a3fb3b482aa..974a77ab8df1cca68b7ac523439a2aaa583f0af5 100644
--- a/Source/WebCore/css/StyleResolver.cpp
+++ b/Source/WebCore/css/StyleResolver.cpp
@@ -2121,16 +2121,30 @@ static bool createGridTrackList(CSSValue* value, Vector<GridTrackSize>& trackSiz
 
 static bool createGridPosition(CSSValue* value, GridPosition& position)
 {
-    // For now, we only accept: <integer> | 'auto'
-    if (!value->isPrimitiveValue())
-        return false;
+    // For now, we only accept: 'auto' | <integer> | span && <integer>?
+    if (value->isPrimitiveValue()) {
+        CSSPrimitiveValue* primitiveValue = static_cast<CSSPrimitiveValue*>(value);
+        if (primitiveValue->getIdent() == CSSValueAuto)
+            return true;
 
-    CSSPrimitiveValue* primitiveValue = static_cast<CSSPrimitiveValue*>(value);
-    if (primitiveValue->getIdent() == CSSValueAuto)
+        if (primitiveValue->getIdent() == CSSValueSpan) {
+            // If the <integer> is omitted, it defaults to '1'.
+            position.setSpanPosition(1);
+            return true;
+        }
+
+        ASSERT(primitiveValue->isNumber());
+        position.setIntegerPosition(primitiveValue->getIntValue());
         return true;
+    }
 
-    ASSERT_WITH_SECURITY_IMPLICATION(primitiveValue->isNumber());
-    position.setIntegerPosition(primitiveValue->getIntValue());
+    ASSERT_WITH_SECURITY_IMPLICATION(value->isValueList());
+    CSSValueList* values = static_cast<CSSValueList*>(value);
+    ASSERT(values->length() == 2);
+    ASSERT_WITH_SECURITY_IMPLICATION(values->itemWithoutBoundsCheck(1)->isPrimitiveValue());
+    CSSPrimitiveValue* numericValue = static_cast<CSSPrimitiveValue*>(values->itemWithoutBoundsCheck(1));
+    ASSERT(numericValue->isNumber());
+    position.setSpanPosition(numericValue->getIntValue());
     return true;
 }