GitLab

FakeTileService now post the callbacks. and invoke the callback for
StartFetchForTiles().

TBR=orinj@chromium.org

Bug: 1077913
Change-Id: I8d06ca1bee02e513ccf2a2cf1838b01004bdb81a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2198638
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: Min Qin <qinmin@chromium.org>
Reviewed-by: Hesen Zhang <hesen@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771245}