Oilpan: revert SVG GC mixin constructor workaround.

Source/core/svg/SVGMaskElement.cpp

Index: Source/core/svg/SVGMaskElement.cpp
diff --git a/Source/core/svg/SVGMaskElement.cpp b/Source/core/svg/SVGMaskElement.cpp
index 8edbb8ce019e9e1ac3dea12d9991db758bf48b69..48e6c3a465db9578fbce635debbbd9dc7a7f8543 100644
--- a/Source/core/svg/SVGMaskElement.cpp
+++ b/Source/core/svg/SVGMaskElement.cpp
@@ -31,6 +31,7 @@ namespace blink {
 
 inline SVGMaskElement::SVGMaskElement(Document& document)
     : SVGElement(SVGNames::maskTag, document)
+    , SVGTests(this)
     , m_x(SVGAnimatedLength::create(this, SVGNames::xAttr, SVGLength::create(SVGLengthMode::Width), AllowNegativeLengths))
     , m_y(SVGAnimatedLength::create(this, SVGNames::yAttr, SVGLength::create(SVGLengthMode::Height), AllowNegativeLengths))
     , m_width(SVGAnimatedLength::create(this, SVGNames::widthAttr, SVGLength::create(SVGLengthMode::Width), ForbidNegativeLengths))
@@ -38,8 +39,6 @@ inline SVGMaskElement::SVGMaskElement(Document& document)
     , m_maskUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::maskUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX))
     , m_maskContentUnits(SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>::create(this, SVGNames::maskContentUnitsAttr, SVGUnitTypes::SVG_UNIT_TYPE_USERSPACEONUSE))
 {
-    SVGTests::initialize(this);
-
     // Spec: If the x/y attribute is not specified, the effect is as if a value of "-10%" were specified.
     m_x->setDefaultValueAsString("-10%");
     m_y->setDefaultValueAsString("-10%");