GitLab

ScriptFinishedCallback can/should be a OnceCallback as
it would only run (at most) once. This makes internal class Handler
take OnceCallbacks too, simplifying the code a bit.

Bug: None
Change-Id: Id74e83ba255c9507ea778a7ad9fef08f8d7b9dbd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2133659
Commit-Queue: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760318}