Oilpan: fix build after r194987.

Source/core/html/HTMLContentElement.h

Index: Source/core/html/HTMLContentElement.h
diff --git a/Source/core/html/HTMLContentElement.h b/Source/core/html/HTMLContentElement.h
index 5ed3b18bdaa77cd19517403da0863fe4c15ff212..d676fbf49e102911ad4509a0b9241ce81f91251c 100644
--- a/Source/core/html/HTMLContentElement.h
+++ b/Source/core/html/HTMLContentElement.h
@@ -38,7 +38,7 @@
 
 namespace blink {
 
-class HTMLContentSelectFilter : public NoBaseWillBeGarbageCollected<HTMLContentSelectFilter> {
+class HTMLContentSelectFilter : public NoBaseWillBeGarbageCollectedFinalized<HTMLContentSelectFilter> {
 public:
     virtual ~HTMLContentSelectFilter() { }
     virtual bool canSelectNode(const WillBeHeapVector<RawPtrWillBeMember<Node>, 32>& siblings, int nth) const = 0;
@@ -59,6 +59,8 @@ public:
     const CSSSelectorList& selectorList() const;
     bool isSelectValid() const;
 
+    DECLARE_VIRTUAL_TRACE();
+
 private:
     HTMLContentElement(Document&, PassOwnPtrWillBeRawPtr<HTMLContentSelectFilter>);