configure(config, isPreload) {
    this.config_ = config;
    if (isPreload) {
      this.isPreload_ = isPreload;
    }
    if (this.expirationTimer_) {
      this.expirationTimer_.tickEvery(
          /* seconds= */ this.config_.updateExpirationTime);
    }
  }
Called by the Player to provide an updated configuration any time it
changes.
Must be called at least once before init().

@param {shaka.extern.DrmConfiguration} config
@param {(function():boolean)=} isPreload