Add support for the column-fill property.

Source/core/page/UseCounter.cpp

Index: Source/core/page/UseCounter.cpp
diff --git a/Source/core/page/UseCounter.cpp b/Source/core/page/UseCounter.cpp
index afe246724b4e6ecae3498b599d57d0e7ee78038a..92e4c8b6bb7556c50e25d7c4deba367fb771c3ec 100644
--- a/Source/core/page/UseCounter.cpp
+++ b/Source/core/page/UseCounter.cpp
@@ -498,6 +498,7 @@ int UseCounter::mapCSSPropertyIdToCSSSampleIdForHistogram(int id)
     case CSSPropertyIsolation: return 436;
     case CSSPropertyObjectPosition: return 437;
     case CSSPropertyInternalCallback: return 438;
+    case CSSPropertyWebkitColumnFill: return 439;
 
     // Add new features above this line (don't change the assigned numbers of the existing
     // items) and update maximumCSSSampleId() with the new maximum value.
@@ -512,7 +513,7 @@ int UseCounter::mapCSSPropertyIdToCSSSampleIdForHistogram(int id)
     return 0;
 }
 
-static int maximumCSSSampleId() { return 438; }
+static int maximumCSSSampleId() { return 439; }
 
 UseCounter::UseCounter()
 {