GitLab

List of changes:
* restructure FeedbackPrivateDelegate to have a more generic interface
* remove unecessary use of unique_ptrs
* change instances of RepeatingCallback to OnceCallback
* factor common DebugDaemonLogSource callback functionality into one callback
* use move semantics to avoid large string copies

BUG=None
TEST=Ensure feedback report upload works

Change-Id: I5b33ab60c727e2a92a08a463e9ad874e5e72b3d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1560516Reviewed-by: Chris Morin <cmtm@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Commit-Queue: Chris Morin <cmtm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#650420}