Conversion from guava ListenableFuture to Scala Future

ListenableFutureToScalaFuture.scala

implicit def toScalaFuture[T](lFuture: ListenableFuture[T]): Future[T] = {
  val p = Promise[T]
  Futures.addCallback(lFuture,
    new FutureCallback[T] {
      def onSuccess(result: T) = p.success(result)
      def onFailure(t: Throwable) = p.failure(t)
    })
  p.future
}

what are the correct import(s) ?

import com.google.common.util.concurrent.{FutureCallback, Futures, ListenableFuture}