Enable the WebUSB Origin Trial.

third_party/WebKit/Source/modules/webusb/USBEndpoint.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.
 
 // http://wicg.github.io/webusb/#endpoints
 
 enum USBDirection {
     "in",
     "out"
 };
 
 enum USBEndpointType {
     "bulk",
     "interrupt",
     "isochronous"
 };
 
 [
     Constructor(USBAlternateInterface alternate, octet endpointNumber, USBDirection direction),
     RaisesException=Constructor,
-    RuntimeEnabled=WebUSB,
+    OriginTrialEnabled=WebUSB,
 ] interface USBEndpoint {
     readonly attribute octet endpointNumber;
     readonly attribute USBDirection direction;
     readonly attribute USBEndpointType type;
     readonly attribute unsigned long packetSize;
 };