getReferenceFromUrl
Creates a StorageReference given a gs:// or https:// URL pointing to a Firebase Storage location.
Return
An instance of StorageReference at the given url.
Parameters
fullUrl
A gs:// or https:// URL used to initialize the reference. For example, you can pass in a download URL retrieved from getDownloadUrl or the uri retrieved from toString An error is thrown if fullUrl is not associated with the FirebaseApp used to initialize this FirebaseStorage.