Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

This CL removes #include to sequenced_worker_pool.h in sequence_checker.h
by hiding its members into a nested class, and adds #include and forward
decls to other files as needed.

Note that the non trivial diffs are in sequence_checker_impl.{h,cc} only.

The header dependency from sequence_checker.h to sequenced_worker_pool.h
prevents other headers to use sequence_checker.h due to a dependency
cycle.

TBR=sky@chromium.org, kinuko@chromium.org, rdsmith@chromium.org, qinmin@chromium.org, marq@chromium.org, rockot@chromium.org, blundell@chromium.org, oshima@chromium.org, slan@chromium.org, boliu@chromium.org

Review-Url: https://codereview.chromium.org/2690533002
Cr-Original-Commit-Position: refs/heads/master@{#450321}
Committed: https://chromium.googlesource.com/chromium/src/+/d502a3f2fa0b673a5082c1d601298bd114a9d237
Review-Url: https://codereview.chromium.org/2690533002
Cr-Commit-Position: refs/heads/master@{#450384}


CrOS-Libchrome-Original-Commit: 70b7c5d796420107930c72d4ad82e0c850166b1a
3 files changed
tree: 379999b471a812546b451fac3569e1f0d4a50162
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/