Remove ENABLE(OILPAN) uses in wtf/

third_party/WebKit/Source/wtf/HashSet.h

Index: third_party/WebKit/Source/wtf/HashSet.h
diff --git a/third_party/WebKit/Source/wtf/HashSet.h b/third_party/WebKit/Source/wtf/HashSet.h
index 752a4c5806257abf25eac52d08268929a3dd0ff7..3b38c17f00e0ccd9fe0e13a1540c049acd00527f 100644
--- a/third_party/WebKit/Source/wtf/HashSet.h
+++ b/third_party/WebKit/Source/wtf/HashSet.h
@@ -271,13 +271,6 @@ inline void copyToVector(const C& collection, W& vector)
         vector[i] = *it;
 }
 
-#if !ENABLE(OILPAN)
-template <typename T, typename U, typename V>
-struct NeedsTracing<HashSet<T, U, V>> {
-    static const bool value = false;
-};
-#endif
-
 } // namespace WTF
 
 using WTF::HashSet;