Remove JsonPrefStore::GetTaskRunnerForFile.

Bug: 667892
Change-Id: I07a16b512814e313be1628d93d3ceacdfb173bb2
Reviewed-on: https://chromium-review.googlesource.com/864839
Commit-Queue: Gabriel Charette <gab@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529278}
2 files changed