anchor.diff:  
     static bool get polymerDesigner =>
         _flags['enable-polymer-designer'] == true;
  +
  +  static bool get enableNewUsbApi =>
  +      _flags['enable-new-usb-api'] == true && PlatformInfo.chromeVersion >= 40;
   
     /**
      * Add new flags to the set, possibly overwriting the existing values.
  
positive.code: 
  import 'dart:async';
  import 'dart:convert' show JSON;
  
  /**
   * Stores global developer flags.
  
negative.code:     "bower-override-dependencies": {
      },
      "bower-use-git-clone": false,
      "package-files-are-editable": false,
      "enable-new-usb-api": true
    };
  
    /**
  