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

third_party/WebKit/Source/core/input/InputDeviceCapabilities.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.
 
 // Represents capabilities for a group of related input devices.
 // To ease implementation, developers cannot rely on comparing two 
 // InputDeviceCapabilities instances for equality. Now we only have two
 // InputDeviceCapabilities instances: one for devices which send touch
 // events, and one for those that don't, because currently all we care
 // about is if the input device fires touch events or not.
 
 [
     Constructor(optional InputDeviceCapabilitiesInit deviceInitDict),
     RuntimeEnabled=InputDeviceCapabilities,
-    GarbageCollected,
 ] interface InputDeviceCapabilities {
     
     // Whether this device dispatches touch events for movement.  This is used to detect
     // mouse events which represent only an action that has already been handled  by
     // touch event handlers.
     [Measure] readonly attribute boolean firesTouchEvents;
 };