Fix JSCompiler error.

remoting/webapp/oauth2.js

 // 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.
 
 /**
  * @fileoverview
  * OAuth2 class that handles retrieval/storage of an OAuth2 token.
  *
  * Uses a content script to trampoline the OAuth redirect page back into the
  * extension context.  This works around the lack of native support for
@@ skipping 208 matching lines @@
       // we return will be valid for at least 2 minutes.
       // If the access token is to be useful, this object must make some
       // guarantee as to how long the token will be valid for.
       // The choice of 2 minutes is arbitrary, but that length of time
       // is part of the contract satisfied by callWithToken().
       // Offset by a further 30 seconds to account for RTT issues.
       this.setAccessToken(tokens['access_token'],
           (tokens['expires_in'] - (120 + 30)) * 1000 + Date.now());
     } catch (err) {
       console.error('Invalid "token" response from server:',
-                    /** @type {*} */ err);
+                    /** @type {*} */ (err));
     }
   } else {
     console.error('Failed to get tokens. Status: ' + xhr.status +
                   ' response: ' + xhr.responseText);
   }
 };
 
 /**
  * Asynchronously retrieves a new access token from the server.
  *
@@ skipping 169 matching lines @@
  * @return {?string} The email address, if it has been cached by a previous call
  *     to getEmail, otherwise null.
  */
 remoting.OAuth2.prototype.getCachedEmail = function() {
   var value = window.localStorage.getItem(this.KEY_EMAIL_);
   if (typeof value == 'string') {
     return value;
   }
   return null;
 };