[scheduler] Disabling lifetime checking for BrowserTaskExecutor.

Lifetime checking, a recent addition to TaskRunners used for testing, needs
to be disabled in the TaskRunners created by BrowserTaskExecutor, the same
way it's currently happening for DefaultTaskExecutor.

Bug: 863341
Change-Id: I73025fb82bb289ce18486eb4121e077133070c72
Reviewed-on: https://chromium-review.googlesource.com/c/1447812
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Karolina Soltys <ksolt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628025}
3 files changed