Stop passing callback_runner into IndexedDBCallbacksImpl

Bug: 717812
Change-Id: Ief0d69e6b676a8fd7456a16acd221851f70bc13f
Reviewed-on: https://chromium-review.googlesource.com/1164471
Commit-Queue: Chase Phillips <cmp@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581707}
9 files changed