Revert "Add --disable-background-tasks flag."

This reverts commit 7b4401f0ecb3645eb61c7e9f7a2b4348bfb036a2.

Reason for revert: Broke Cronet tests:
https://ci.chromium.org/buildbot/chromium.android/Android%20Cronet%20Marshmallow%2064bit%20Perf/16545

Original change's description:
> Add --disable-background-tasks flag.
> 
> This flag delays execution of base::TaskPriority::BACKGROUND tasks
> until shutdown.
> 
> Bug: 726937
> Change-Id: I2ce529a410382e7199558a0ed95476767b14786b
> Reviewed-on: https://chromium-review.googlesource.com/919866
> Commit-Queue: François Doray <fdoray@chromium.org>
> Reviewed-by: John Abd-El-Malek <jam@chromium.org>
> Reviewed-by: Tommy Martino <tmartino@chromium.org>
> Reviewed-by: Robert Liao <robliao@chromium.org>
> Reviewed-by: Gabriel Charette <gab@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#537862}

TBR=gab@chromium.org,jam@chromium.org,fdoray@chromium.org,robliao@chromium.org,tmartino@chromium.org

Change-Id: Ibc7b70e5bdebd953ad6397507bd1f0673622942f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 726937
Reviewed-on: https://chromium-review.googlesource.com/927282
Reviewed-by: Andrei Kapishnikov <kapishnikov@chromium.org>
Commit-Queue: Andrei Kapishnikov <kapishnikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537943}

CrOS-Libchrome-Original-Commit: bc8ef3f79ae198d7527e10dedbae19a76772826c
6 files changed
tree: ab057033f7c72a779d5d4493c6b8ec7bfd56ba3f
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/