| Index: inject.preload.js | 
| =================================================================== | 
| --- a/inject.preload.js | 
| +++ b/inject.preload.js | 
| @@ -174,8 +174,11 @@ | 
| { | 
| for (let name of properties) | 
| { | 
| -      Object.defineProperty(dest, name, | 
| -                            Object.getOwnPropertyDescriptor(src, name)); | 
| +      if (src.hasOwnProperty(name)) | 
| +      { | 
| +        Object.defineProperty(dest, name, | 
| +                              Object.getOwnPropertyDescriptor(src, name)); | 
| +      } | 
| } | 
| } | 
|  | 
| @@ -375,6 +378,7 @@ | 
| WrappedRTCPeerConnection.prototype = RealRTCPeerConnection.prototype; | 
|  | 
| let boundWrappedRTCPeerConnection = WrappedRTCPeerConnection.bind(); | 
| +  // NOTE: Edge does not support generateCertificate | 
| copyProperties(RealRTCPeerConnection, boundWrappedRTCPeerConnection, | 
| ["generateCertificate", "name", "prototype"]); | 
| RealRTCPeerConnection.prototype.constructor = boundWrappedRTCPeerConnection; | 
|  |