Propagate task queue to create test::DirectTransport by TaskQueueBase interface

actual task queue implementation for these tests is intentionally unchanged for now.

while at it, change return type of created transports to unique_ptr to note passing ownership.

Bug: webrtc:10933
Change-Id: I324597b503e647c471f43511340eb9c07ba03ee8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/154743
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29335}
diff --git a/audio/BUILD.gn b/audio/BUILD.gn
index b24584c..fa16bb7 100644
--- a/audio/BUILD.gn
+++ b/audio/BUILD.gn
@@ -102,6 +102,7 @@
     deps = [
       ":audio",
       "../api:simulated_network_api",
+      "../api/task_queue",
       "../call:fake_network",
       "../call:simulated_network",
       "../system_wrappers",