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

third_party/WebKit/Source/modules/bluetooth/BluetoothUUID.idl

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // https://webbluetoothchrome.github.io/web-bluetooth/#idl-def-bluetoothuuid
 
 // Implement BluetoothUUID: http://crbug.com/491441
 // Significant TODOs remain in BluetoothUUID.cpp.
 
 [
-    GarbageCollected,
     OriginTrialEnabled=WebBluetooth,
 ] interface BluetoothUUID {
     [RaisesException] static UUID getService((DOMString or unsigned long) name);
     [RaisesException] static UUID getCharacteristic((DOMString or unsigned long) name);
     [RaisesException] static UUID getDescriptor((DOMString or unsigned long) name);
 
     static UUID canonicalUUID([EnforceRange] unsigned long alias);
 };
 
 typedef DOMString UUID;
 
 typedef (DOMString or unsigned long) BluetoothServiceUUID;
 
 typedef (DOMString or unsigned long) BluetoothCharacteristicUUID;
 
 typedef (DOMString or unsigned long) BluetoothDescriptorUUID;