sync_ui_util: Use SyncService rather than ProfileSyncService

Generally, everything should use the interface (SyncService) rather than
the concrete implementation (ProfileSyncService). In particular, this
will make it easier to write tests for this code, since they can now use
TestSyncService instead of ProfileSyncServiceMock.

Bug: 884159, 910518
Change-Id: I794e0af45b4fc576536265cbc049358d37196cbd
Reviewed-on: https://chromium-review.googlesource.com/c/1357087
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613916}
4 files changed