ServiceWorker: BindOnce refactoring

BUG=714018

Change-Id: I348d7b85d4cf3fa68279ac9797b4223c4168cdc2
Reviewed-on: https://chromium-review.googlesource.com/981500
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Commit-Queue: Mark Pilgrim <pilgrim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546288}
1 file changed