Have bindings layer assume and insist that all interface types are GCed.

third_party/WebKit/Source/modules/indexeddb/IDBDatabase.idl

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 12 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // https://w3c.github.io/IndexedDB/#idl-def-IDBDatabase
 
 [
     ActiveScriptWrappable,
     DependentLifetime,
     Exposed=(Window,Worker),
-    GarbageCollected,
 ] interface IDBDatabase : EventTarget {
     readonly attribute DOMString name;
     readonly attribute unsigned long long version;
     [Measure] readonly attribute DOMStringList objectStoreNames;
 
     [RaisesException] IDBObjectStore createObjectStore(DOMString name, optional IDBObjectStoreParameters options);
     [RaisesException] void deleteObjectStore(DOMString name);
     [CallWith=ScriptState, RaisesException] IDBTransaction transaction((DOMString or sequence<DOMString> or DOMStringList) storeNames, optional IDBTransactionMode mode = "readonly");
     void close();
 
     attribute EventHandler onabort;
     attribute EventHandler onclose;
     attribute EventHandler onerror;
     attribute EventHandler onversionchange;
 };