Oilpan: revert SVG GC mixin constructor workaround.

Source/core/svg/SVGScriptElement.cpp

Index: Source/core/svg/SVGScriptElement.cpp
diff --git a/Source/core/svg/SVGScriptElement.cpp b/Source/core/svg/SVGScriptElement.cpp
index 2722fb3a1e55458cf42f17e14b498164143e5e02..2fde30895e2c5f3855a23b3c95c0fd1b00db23d2 100644
--- a/Source/core/svg/SVGScriptElement.cpp
+++ b/Source/core/svg/SVGScriptElement.cpp
@@ -34,10 +34,10 @@ namespace blink {
 
 inline SVGScriptElement::SVGScriptElement(Document& document, bool wasInsertedByParser, bool alreadyStarted)
     : SVGElement(SVGNames::scriptTag, document)
+    , SVGURIReference(this)
     , m_svgLoadEventTimer(this, &SVGElement::svgLoadEventTimerFired)
     , m_loader(ScriptLoader::create(this, wasInsertedByParser, alreadyStarted))
 {
-    SVGURIReference::initialize(this);
 }
 
 PassRefPtrWillBeRawPtr<SVGScriptElement> SVGScriptElement::create(Document& document, bool insertedByParser)