[Extensions Callback Cleanup] Miscellaneous Installation Util

Do the following clean-ups in some miscellaneous installation utility
classes/files in extensions code:
- Convert base::Callback to base::RepeatingCallback/base::OnceCallback
- Convert base::Bind to base::BindRepeating/base::BindOnce
- Pass callbacks by value when an instance is retained

Bug: 714018

Change-Id: Ia58a8467b6956bdf2bd15557d51f312e9cc0a4cc
Reviewed-on: https://chromium-review.googlesource.com/c/1391866
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619835}
11 files changed