Remove SyncService::RequestStop

RequestStop(KEEP_DATA) has been replaced by
SyncUserSettings::SetSyncRequested(false). RequestStop(CLEAR_DATA) is
being replaced in this CL by a new StopAndClear().

Bug: 884159
Change-Id: I0d94ee4e834114c062c79bfc10c188276cc294d8
Reviewed-on: https://chromium-review.googlesource.com/c/1353944
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612628}
19 files changed