Use FileDescriptorWatcher in FilePathWatcherKQueue.

This allows FilePathWatcherKQueue to be used from any thread that
instantiates a FileDescriptorWatcher (not just threads that run
a MessageLoopForIO). This will facilitate the migration of
BrowserThreads to base/task_scheduler.

BUG=645114

Review-Url: https://codereview.chromium.org/2353103002
Cr-Commit-Position: refs/heads/master@{#422243}


CrOS-Libchrome-Original-Commit: a0e4a7ead3bae88770f4352e2dd927998238b9ee
4 files changed
tree: aa743def4afd2ce276a2c1a5cbec0262f21bff59
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/