Change ITestClient to be similar to IChildProcessService.

Preparing the MultiprocessTestClientLauncher for transitioning to the
new base ChildProcessLauncher. More specifically, making ITestClient
similar to IChildProcessService. This requires moving extra methods to
a new interface ITestController, and creating a callback interface
ITestCallback that lets the service sets the ITestController interface
on the client.

BUG=702316

Review-Url: https://codereview.chromium.org/2781913002
Cr-Commit-Position: refs/heads/master@{#462683}


CrOS-Libchrome-Original-Commit: 9bd4d39997fab20c32cd0c7a75c45dbcf3f00642
6 files changed
tree: 60029170a82c7c5add4a7d2cce81e2b927e08b61
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/