[Bookmarks Bar] Update naming of utils methods for clarity

This CL has no functional changes. We update some naming of utils
methods to make it clearer when we add a new parallel preference in
upcoming CLs.

Bug: 440359932
Change-Id: I2685a35508ecb2e131f4c076da25a64713a703b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6872471
Auto-Submit: Mark Schillaci <mschillaci@google.com>
Commit-Queue: Mark Schillaci <mschillaci@google.com>
Reviewed-by: Eleanor Lee <eleanorlee@google.com>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1505887}