Remove more oilpan.

sky/engine/core/html/imports/HTMLImportsController.h

Index: sky/engine/core/html/imports/HTMLImportsController.h
diff --git a/sky/engine/core/html/imports/HTMLImportsController.h b/sky/engine/core/html/imports/HTMLImportsController.h
index 640e1f950b2e65963432d843cb56e55447546bea..4e9622363b4ff09bee46c7cbc93d837c49e7376d 100644
--- a/sky/engine/core/html/imports/HTMLImportsController.h
+++ b/sky/engine/core/html/imports/HTMLImportsController.h
@@ -50,9 +50,8 @@ class HTMLImportChildClient;
 class HTMLImportLoader;
 class HTMLImportTreeRoot;
 
-class HTMLImportsController final : public DummyBase<HTMLImportsController>, public DocumentSupplement {
-    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLImportsController);
-    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
+class HTMLImportsController final : public DocumentSupplement {
+    WTF_MAKE_FAST_ALLOCATED;
 public:
     static const char* supplementName();
     static void provideTo(Document&);