Oilpan: fix build after r197794.

Source/modules/navigatorconnect/ServicePortCollection.h

Index: Source/modules/navigatorconnect/ServicePortCollection.h
diff --git a/Source/modules/navigatorconnect/ServicePortCollection.h b/Source/modules/navigatorconnect/ServicePortCollection.h
index a49a417260065f65a21ce4a0304f0c69418f0e6c..b44b11c5af3b0fc166ef805344e0a711efce8e37 100644
--- a/Source/modules/navigatorconnect/ServicePortCollection.h
+++ b/Source/modules/navigatorconnect/ServicePortCollection.h
@@ -9,6 +9,7 @@
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/events/EventTarget.h"
 #include "modules/ModulesExport.h"
+#include "platform/heap/Handle.h"
 #include "public/platform/modules/navigator_services/WebServicePortProvider.h"
 #include "public/platform/modules/navigator_services/WebServicePortProviderClient.h"
 #include "wtf/RefCounted.h"
@@ -26,6 +27,7 @@ class MODULES_EXPORT ServicePortCollection final
     DEFINE_WRAPPERTYPEINFO();
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(ServicePortCollection);
     WTF_MAKE_NONCOPYABLE(ServicePortCollection);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(ServicePortCollection);
 public:
     static ServicePortCollection* create(ExecutionContext*);
     ~ServicePortCollection() override;