Experimental USB API

chrome/common/extensions/api/_permission_features.json

 // Copyright (c) 2012 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.
 
 {
   "appNotifications": {
     "channel": "stable",
     "extension_types": ["packaged_app", "hosted_app"]
   },
   "background": {
@@ skipping 202 matching lines @@
   "ttsEngine": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app", "platform_app"]
   },
   "unlimitedStorage": {
     "channel": "stable",
     "extension_types": [
       "extension", "packaged_app", "hosted_app", "platform_app"
     ]
   },
+  "usb": {
+    "channel": "stable",
+    "extension_types": ["platform_app"]
+  },
   "webNavigation": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webSocketProxyPrivate": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"],
     "whitelist": [
       "haiffjcadagjlijoggckpgfnoeiflnem",  // Citrix Receiver
       "gnedhmakppccajfpfiihfcdlnpgomkcf",  // Citrix Receiver Beta
@@ skipping 12 matching lines @@
   },
   "webRequest": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   },
   "webRequestBlocking": {
     "channel": "stable",
     "extension_types": ["extension", "packaged_app"]
   }
 }