Open MessagePumpLibevent's pipe with O_CLOEXEC

This prevents the pipe's fds from being leaked into child processes.

TEST=git cl try
BUG=653930

Review-Url: https://codereview.chromium.org/2394413002
Cr-Commit-Position: refs/heads/master@{#423899}


CrOS-Libchrome-Original-Commit: f9c8562e55b669915faf87d8d7eda32ae62bf661
3 files changed
tree: f4fe2a157836622e801dedd3d9b9e91147b80e0f
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/