Oilpan: Fix weak processing for IntersectionObserver::m_root

third_party/WebKit/Source/core/dom/IntersectionObserver.h

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.h b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
index a918acb4cab2f8f6a182a4fbfbeecd9ebbc6672f..30a2f2e37c3a9e816e8df993fac0757dda0eb69d 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.h
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
@@ -27,7 +27,6 @@ class IntersectionObserver final : public GarbageCollectedFinalized<Intersection
 public:
     static IntersectionObserver* create(const IntersectionObserverInit&, IntersectionObserverCallback&, ExceptionState&);
     static void resumeSuspendedObservers();
-    static void rootDisappearedCallback(Visitor*, void*);
 
     // API methods
     void observe(Element*, ExceptionState&);
@@ -56,6 +55,7 @@ public:
 
 private:
     explicit IntersectionObserver(IntersectionObserverCallback&, Node&, const Vector<Length>& rootMargin, const Vector<float>& thresholds);
+    void clearWeakMembers(Visitor*);
 
     Member<IntersectionObserverCallback> m_callback;
     WeakPtrWillBeWeakMember<Node> m_root;