code: function(options, callback) {
    this.options = extend({ redirectUri: 'postmessage'}, options);
    this.name = 'google';
    this.keyManager = new KeyManager();
    this.callback = callback;
  }
docs: @callback GooglePlusStrategyCallback
  @param {Object} tokens Available tokens. May include access and/or refresh tokens
  @param {Object} profile User profile
  @param {CompletionCallback} done Callback to indicate completion of auth
   
  Configure the Google+ Sign-In strategy
  
  @constructor
  @param {Object} options configuration
  @param {String} [options.apiKey] API Key for your project
  @param {String} [options.clientId] Client ID from the APIs console, must match ID configured in button
  @param {String} [options.clientSecret] Corresponding client secret. Only needed if requesting offline access
  @param {String[]} [options.presenters] Array of valid client IDs that are authorized to present ID tokens
  @param {Boolean} [options.skipProfile] True if user profile isn't needed.
  @param {String} [options.redirectUri] Redirect URI as configured for the app. Defaults to 'postmessage'
  @param {Boolean} [options.passReqToCallback] True if request should be propagated to the callback as 1st arg.
  @param {GooglePlusStrategyCallback} callback Callback function once authorization is completed.