Remove usage of FILE thread from interstitial controller client

Bug: 689520
Change-Id: I8608691b69c5cfa66d1937403fb8a0476a7cf7aa
Reviewed-on: https://chromium-review.googlesource.com/592449
Commit-Queue: Mustafa Emre Acer <meacer@chromium.org>
Reviewed-by: Adrienne Porter Felt <felt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490614}
1 file changed