floop: close output iodev when no stream attached

Remember to close the floop internal device when all streams are removed.

BUG=b:362679648
TEST=stop audio stream when recording from floop device \
     output floop device should be closed

Change-Id: Ia3bf98e5a17278e859bb51589f9380301431eeca
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/5890787
Reviewed-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Commit-Queue: Terry Cheong <htcheong@chromium.org>
Tested-by: chromeos-cop-builder@chromeos-cop.iam.gserviceaccount.com <chromeos-cop-builder@chromeos-cop.iam.gserviceaccount.com>
Reviewed-by: Li-Yu Yu <aaronyu@google.com>

cras/src/server/cras_iodev_list.c

@@ -1435,6 +1435,17 @@ static int possibly_close_enabled_devs(enum CRAS_STREAM_DIRECTION dir) {
     idle_dev_check(NULL, NULL);
   }
 
+  // Flexible loopback (internal) devices are not enabled
+  // and should not have pinned streams.
+  if (dir == CRAS_STREAM_OUTPUT) {
+    struct cras_floop_pair* fpair;
+    DL_FOREACH (floop_pair_list, fpair) {
+      if (cras_iodev_is_open(&fpair->output)) {
+        cras_iodev_list_disable_floop_pair(fpair);
+      }
+    }
+  }
+
   return 0;
 }