BackgroundTaskRunner: automatically create a queue if necessary
Requiring all users to go create a queue themselves is extra boilerplate,
and rarely desired. Instead, have the context manager yield the queue,
and have it generate an instance if the passed in value was None.
BUG=None
TEST=unittests updated.
Change-Id: I9071227c5254e1b6b8e4da7ed52c21f51a83aaad
Reviewed-on: https://gerrit.chromium.org/gerrit/39387
Reviewed-by: David James <davidjames@chromium.org>
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
6 files changed
