Use initializer_lists for static WTF::HashSets.

third_party/WebKit/Source/core/svg/SVGLength.cpp

Index: third_party/WebKit/Source/core/svg/SVGLength.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGLength.cpp b/third_party/WebKit/Source/core/svg/SVGLength.cpp
index c5fe9da82225eadcf9229ea49e446e1f58833d29..f8000e9b5898794b03601bedafc3de819a27ab2d 100644
--- a/third_party/WebKit/Source/core/svg/SVGLength.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGLength.cpp
@@ -212,21 +212,18 @@ SVGLengthMode SVGLength::lengthModeForAnimatedLengthAttribute(const QualifiedNam
 
 bool SVGLength::negativeValuesForbiddenForAnimatedLengthAttribute(const QualifiedName& attrName)
 {
-    DEFINE_STATIC_LOCAL(HashSet<QualifiedName>, s_noNegativeValuesSet, ());
-
-    if (s_noNegativeValuesSet.isEmpty()) {
-        s_noNegativeValuesSet.add(SVGNames::frAttr);
-        s_noNegativeValuesSet.add(SVGNames::rAttr);
-        s_noNegativeValuesSet.add(SVGNames::rxAttr);
-        s_noNegativeValuesSet.add(SVGNames::ryAttr);
-        s_noNegativeValuesSet.add(SVGNames::widthAttr);
-        s_noNegativeValuesSet.add(SVGNames::heightAttr);
-        s_noNegativeValuesSet.add(SVGNames::markerWidthAttr);
-        s_noNegativeValuesSet.add(SVGNames::markerHeightAttr);
-        s_noNegativeValuesSet.add(SVGNames::textLengthAttr);
-    }
-
-    return s_noNegativeValuesSet.contains(attrName);
+    DEFINE_STATIC_LOCAL(HashSet<QualifiedName>, noNegativeValuesSet, ({
+        SVGNames::frAttr,
+        SVGNames::rAttr,
+        SVGNames::rxAttr,
+        SVGNames::ryAttr,
+        SVGNames::widthAttr,
+        SVGNames::heightAttr,
+        SVGNames::markerWidthAttr,
+        SVGNames::markerHeightAttr,
+        SVGNames::textLengthAttr,
+    }));
+    return noNegativeValuesSet.contains(attrName);
 }
 
 void SVGLength::add(SVGPropertyBase* other, SVGElement* contextElement)