SourceInfo in getSourceInfos - dictionary or interface?

We've run across an implementation issue in Blink: Returning 
dictionaries is still an unimplemented feature.

Currently the WebIDL for the getSourceInfos is:

interface MediaStreamTrack {
     static sequence<SourceInfo> getSourceInfos()
}

dictionary SourceInfo {
    DOMString id;  // same as "sourceid" in previous proposal
    DOMString kind;  // "video" or "audio"
    DOMString label;  // only present if authorized
    VideoFacingModeEnum facing;  // only for video sources
}

It wouldn't make much difference in Javascript, I think, if instead we said:

*

interface MediaStreamTrack {

    static sequence<SourceInfo> getSourceInfos()

}


*interface* SourceInfo {

   DOMString id;  // same as "sourceid" in previous proposal

   DOMString kind;  // "video" or "audio"

   DOMString label?;  // only present if authorized

   VideoFacingModeEnum facing?;  // only for video sources

}

*
But the implementation would be easier.
Would anyone mind?

           Harald