Web Animations CSS: Handle border-spacing property

Source/core/css/resolver/AnimatedStyleBuilder.cpp

Index: Source/core/css/resolver/AnimatedStyleBuilder.cpp
diff --git a/Source/core/css/resolver/AnimatedStyleBuilder.cpp b/Source/core/css/resolver/AnimatedStyleBuilder.cpp
index 8959a63b5a92248dbccf6588b9509f82fb4b5137..d58c95bcd2088bff8dedbb46df52d739f387c3f9 100644
--- a/Source/core/css/resolver/AnimatedStyleBuilder.cpp
+++ b/Source/core/css/resolver/AnimatedStyleBuilder.cpp
@@ -213,6 +213,12 @@ void AnimatedStyleBuilder::applyProperty(CSSPropertyID property, StyleResolverSt
     case CSSPropertyTop:
         style->setTop(animatableValueToLength(value, state));
         return;
+    case CSSPropertyWebkitBorderHorizontalSpacing:
+        style->setHorizontalBorderSpacing(animatableValueRoundClampTo<unsigned short>(value));
+        return;
+    case CSSPropertyWebkitBorderVerticalSpacing:
+        style->setVerticalBorderSpacing(animatableValueRoundClampTo<unsigned short>(value));
+        return;
     case CSSPropertyWebkitColumnRuleColor:
         style->setColumnRuleColor(toAnimatableColor(value)->color());
         style->setVisitedLinkColumnRuleColor(toAnimatableColor(value)->visitedLinkColor());