Fix race and remove unused features in cryptotoken extension

chrome/browser/resources/cryptotoken/llusbgnubby.js

 // Copyright 2014 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.
 
 /**
  * @fileoverview Implements a low-level gnubby driver based on chrome.usb.
  */
 'use strict';
 
 /**
@@ skipping 28 matching lines @@
 /**
  * Namespace for the llUsbGnubby implementation.
  * @const
  */
 llUsbGnubby.NAMESPACE = 'usb';
 
 /** Destroys this low-level device instance. */
 llUsbGnubby.prototype.destroy = function() {
   if (!this.dev) return;  // Already dead.
 
+  this.gnubbies_.removeOpenDevice(
+      {namespace: llUsbGnubby.NAMESPACE, device: this.id});
   this.closing = true;
 
   console.log(UTIL_fmt('llUsbGnubby.destroy()'));
 
   // Synthesize a close error frame to alert all clients,
   // some of which might be in read state.
   //
   // Use magic CID 0 to address all.
   this.publishFrame_(new Uint8Array([
         0, 0, 0, 0,  // broadcast CID
         llGnubby.CMD_ERROR,
         0, 1,  // length
         llGnubby.GONE]).buffer);
 
   // Set all clients to closed status and remove them.
   while (this.clients.length != 0) {
     var client = this.clients.shift();
     if (client) client.closed = true;
   }
 
   if (this.lockTID) {
     window.clearTimeout(this.lockTID);
     this.lockTID = null;
   }
 
   var dev = this.dev;
   this.dev = null;
 
-  var self = this;
-
-  function onClosed() {
-    console.log(UTIL_fmt('Device ' + dev.handle + ' closed'));
-    self.gnubbies_.removeOpenDevice(
-        {namespace: llUsbGnubby.NAMESPACE, device: self.id});
-  }
-
-  // Release first.
   chrome.usb.releaseInterface(dev, 0, function() {
     console.log(UTIL_fmt('Device ' + dev.handle + ' released'));
-    chrome.usb.closeDevice(dev, onClosed);
+    chrome.usb.closeDevice(dev, function() {
+      console.log(UTIL_fmt('Device ' + dev.handle + ' closed'));
+    });
   });
 };
 
 /**
  * Push frame to all clients.
  * @param {ArrayBuffer} f Data frame
  * @private
  */
 llUsbGnubby.prototype.publishFrame_ = function(f) {
   var old = this.clients;
@@ skipping 237 matching lines @@
           this.lockMillis);
     }
   }
 };
 
 /**
  * Queue command to be sent.
  * If queue was empty, initiate the write.
  * @param {number} cid The client's channel ID.
  * @param {number} cmd The command to send.
- * @param {ArrayBuffer} data Command argument data
+ * @param {ArrayBuffer|Uint8Array} data Command argument data
  */
 llUsbGnubby.prototype.queueCommand = function(cid, cmd, data) {
   if (!this.dev) return;
   if (!this.checkLock_(cid, cmd)) return;
 
   var u8 = new Uint8Array(data);
   var frame = new Uint8Array(u8.length + 7);
 
   frame[0] = cid >>> 24;
   frame[1] = cid >>> 16;
@@ skipping 114 matching lines @@
  * @param {Gnubbies} gnubbies Gnubbies singleton instance
  */
 llUsbGnubby.register = function(gnubbies) {
   var USB_GNUBBY_IMPL = {
     enumerate: llUsbGnubby.enumerate,
     deviceToDeviceId: llUsbGnubby.deviceToDeviceId,
     open: llUsbGnubby.open
   };
   gnubbies.registerNamespace(llUsbGnubby.NAMESPACE, USB_GNUBBY_IMPL);
 };