Change dbus Get/Set Property callback to OnceCallback.

These callbacks are only called once, so change them to the correct
spelling. This will allow bluetooth code to be converted to OnceCallback
as well, which will then allow content code to be converted.

TBR=hashimoto,rkc

Bug: 953861
Change-Id: I49b0fcf6e00721e5e6bbb4439bad7c5cbb0d6463
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1572204
Commit-Queue: danakj <danakj@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Auto-Submit: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652169}
10 files changed