Add support for the column-fill property.

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 e72671d043705578984b139e573181380f862c4b..1de85b7612d041f909b5b6e9a8781c7a5a40e634 100644
--- a/Source/core/css/CSSParser-in.cpp
+++ b/Source/core/css/CSSParser-in.cpp
@@ -794,6 +794,10 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
     case CSSPropertyInternalCallback:
         // This property is only injected programmatically, not parsed from stylesheets.
         return false;
+    case CSSPropertyWebkitColumnFill:
+        if (valueID == CSSValueAuto || valueID == CSSValueBalance)
+            return true;
+        break;
     case CSSPropertyAlignContent:
          if (valueID == CSSValueFlexStart || valueID == CSSValueFlexEnd || valueID == CSSValueCenter || valueID == CSSValueSpaceBetween || valueID == CSSValueSpaceAround || valueID == CSSValueStretch)
              return true;
@@ -1010,6 +1014,7 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyWebkitColumnBreakAfter:
     case CSSPropertyWebkitColumnBreakBefore:
     case CSSPropertyWebkitColumnBreakInside:
+    case CSSPropertyWebkitColumnFill:
     case CSSPropertyWebkitColumnRuleStyle:
     case CSSPropertyAlignContent:
     case CSSPropertyAlignItems:
@@ -2855,6 +2860,7 @@ bool CSSParser::parseValue(CSSPropertyID propId, bool important)
     case CSSPropertyWebkitColumnBreakAfter:
     case CSSPropertyWebkitColumnBreakBefore:
     case CSSPropertyWebkitColumnBreakInside:
+    case CSSPropertyWebkitColumnFill:
     case CSSPropertyWebkitColumnRuleStyle:
     case CSSPropertyAlignContent:
     case CSSPropertyAlignItems: