Delete unused ProfileSyncServiceTestHelper

Bug: none
Change-Id: I40d7e737c56de65d5ccae9196d7a3171a9fda2a7
Reviewed-on: https://chromium-review.googlesource.com/c/1414893
Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623217}
2 files changed