Revert "Reland: Use a per-frame task runner at mojom::SafeBrowsing binding"

This reverts commit 23416d1cede8c6aa875bb86b59bc2b3a9392916d.

Reason for revert: Introduce flakiness again: https://analysis.chromium.org/p/chromium/flake-portal/analysis/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vMjM0MTZkMWNlZGU4YzZhYTg3NWJiODZiNTliYzJiM2E5MzkyOTE2ZAw

Original change's description:
> Reland: Use a per-frame task runner at mojom::SafeBrowsing binding
> 
> This is reland of https://chromium-review.googlesource.com/c/chromium/src/+/1536036
> This was reverted once since ServiceWorkerTest.UpdateRefreshesServiceWorker
> became flaky on Windows, but now this doesn't, though the reason is unclear.
> 
> This CL switches task runners at several places from per-thread to
> per-frame. The purpose of this change is to make it possible to freeze
> tasks for bfcache.
> 
> We found an actual case that JavaScript is executed:
> ./tools/perf/run_tests benchmarks.system_health_smoke_test.SystemHealthBenchmarkSmokeTest.system_health.memory_desktop/load:media:soundcloud:2018
> 
> As this is a non-standard JavaScript API execution, we adopted
> kInternalDefault as the task type.
> 
> Bug: 913912
> Change-Id: Id03b1ac9f46e6c69adea8cd42c6af193dd83fa36
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1578144
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Commit-Queue: Hajime Hoshi <hajimehoshi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#653490}

TBR=avi@chromium.org,hajimehoshi@chromium.org,altimin@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 913912
Change-Id: I6b0156f3ef500c4da7e8c743a755c867cd9496dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1584520
Reviewed-by: Hajime Hoshi <hajimehoshi@chromium.org>
Commit-Queue: Hajime Hoshi <hajimehoshi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654137}
2 files changed