Revert of Remove unnecessary lock that causes reentry. (patchset #2 id:20001 of https://codereview.chromium.org/1865303004/ )

Reason for revert:
Going to do it just a bit different.

Original issue's description:
> Remove unnecessary lock that causes reentry.
>
> The StatisticsRecorder is acquiring a lock before
> calling Import but the import calls back to the SR
> which again tries to acquire the lock... and crashes.
>
> The lock isn't necessary with the new persistent
> iterator (which is lock-free) so move the Import
> call outside of the locking.
>
> BUG=546019
> TBR=asvitkine
>
> Committed: https://crrev.com/fb54f51c8439575d53159e63dee651278434db9f
> Cr-Commit-Position: refs/heads/master@{#385991}

TBR=asvitkine@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=546019

Review URL: https://codereview.chromium.org/1873623003

Cr-Commit-Position: refs/heads/master@{#385997}


CrOS-Libchrome-Original-Commit: af82015c2d329b808c1cebcf4907970e487b1c1b
2 files changed
tree: 9bb5daac8aca0d40bb82dd5af044e8dcdf5a86fa
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/