MultiProcessTest: Update SpawnChild* to return a Process.

We should not be dealing with raw handles.

BUG=417532

Review URL: https://codereview.chromium.org/843113003

Cr-Commit-Position: refs/heads/master@{#311127}


CrOS-Libchrome-Original-Commit: 07b589c1f6c4d0aac24e270a13fa83031bf2038c
16 files changed
tree: a88d2c435c9d2e149b6f5af19edc1837ec51494e
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/