[Oilpan] Replace raw pointer with UntracedMember

third_party/WebKit/Source/core/frame/LocalFrame.h

Index: third_party/WebKit/Source/core/frame/LocalFrame.h
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.h b/third_party/WebKit/Source/core/frame/LocalFrame.h
index 03af3b9113454b72855eedf6cda93993578d4f34..c5eb7a7ae44e62cbe6e03a4e2e4e95ac11c77639 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.h
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.h
@@ -242,8 +242,7 @@ private:
     // weak callback, the set itself is not on the heap and the
     // references are bare pointers (rather than WeakMembers.)
     // See LocalFrame::clearWeakMembers().
-    GC_PLUGIN_IGNORE("553613")
-    HashSet<HTMLPlugInElement*> m_pluginElements;
+    HashSet<UntracedMember<HTMLPlugInElement>> m_pluginElements;
 #endif
 
     float m_pageZoomFactor;