Enable 3rd party support for Security Keys.

chrome/browser/resources/cryptotoken/singlesigner.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 A single gnubby signer wraps the process of opening a gnubby,
  * signing each challenge in an array of challenges until a success condition
  * is satisfied, and finally yielding the gnubby upon success.
  *
  */
@@ skipping 235 matching lines @@
   }
 };
 
 /**
  * Called with the result of a version command.
  * @param {number} rc Result of version command.
  * @param {ArrayBuffer=} opt_data Version.
  * @private
  */
 SingleGnubbySigner.prototype.versionCallback_ = function(rc, opt_data) {
+  if (rc == DeviceStatusCodes.BUSY_STATUS) {
+    if (this.timer_ && this.timer_.expired()) {
+      this.goToError_(DeviceStatusCodes.TIMEOUT_STATUS);
+      return;
+    }
+    // There's still time: resync and retry.
+    var self = this;
+    this.gnubby_.sync(function(code) {
+      if (code) {
+        self.goToError_(code, true);
+        return;
+      }
+      self.gnubby_.version(self.versionCallback_.bind(self));
+    });
+    return;
+  }
   if (rc) {
     this.goToError_(rc, true);
     return;
   }
   this.state_ = SingleGnubbySigner.State.IDLE;
   this.version_ = UTIL_BytesToString(new Uint8Array(opt_data || []));
   this.doSign_(this.challengeIndex_);
 };
 
 /**
@@ skipping 185 matching lines @@
       result['challenge'] = opt_challenge;
     }
     if (opt_info) {
       result['info'] = opt_info;
     }
   }
   this.completeCb_(result);
   // this.gnubby_ is now owned by completeCb_.
   this.gnubby_ = null;
 };