Allow mojo_runner to connect to arbitrary executables.

Allow mojo_runner to connect to arbitrary executables.

- Introduces a new scheme "exe" which loads an executable alongside mojo_runner. TODO is some more security checking around this to prevent arbitrary apps from launching executables but since this is implemented in mojo_runner it's not in any production code right now.
- Includes an apptest of a .mojo app that connects to an executable and binds a service provided by it.
- Creates a new child library that makes it easy to bring up a runner controller thread in an arbitrary executable.

R=jam@chromium.org
http://crbug.com/548694

Committed: https://crrev.com/48799d724056efafd4bc7faa6e77459fbd1efad0
Cr-Commit-Position: refs/heads/master@{#357034}

[jam, 2015-10-29 22:10:17]

lgtm

https://codereview.chromium.org/1419293003/diff/20001/mojo/runner/child/nativ...
File mojo/runner/child/native_service.mojom (right):

https://codereview.chromium.org/1419293003/diff/20001/mojo/runner/child/nativ...
mojo/runner/child/native_service.mojom:1: // Copyright 2015 The Chromium
Authors. All rights reserved.
nit: put test in filename & interface name to make it clear that this is for
testing only?

[Ben Goodger (Google), 2015-10-29 22:40:15]

The CQ bit was checked by ben@chromium.org

[Ben Goodger (Google), 2015-10-29 22:40:15]

The patchset sent to the CQ was uploaded after l-g-t-m from jam@chromium.org
Link to the patchset: https://codereview.chromium.org/1419293003/#ps40001
(title: ".")

[commit-bot: I haz the power, 2015-10-29 22:41:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1419293003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1419293003/40001

[commit-bot: I haz the power, 2015-10-29 23:25:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-29 23:25:55]

Try jobs failed on following builders:
  linux_chromium_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[Ben Goodger (Google), 2015-10-30 01:48:05]

The CQ bit was checked by ben@chromium.org

[Ben Goodger (Google), 2015-10-30 01:48:05]

The patchset sent to the CQ was uploaded after l-g-t-m from jam@chromium.org
Link to the patchset: https://codereview.chromium.org/1419293003/#ps60001
(title: ".")

[commit-bot: I haz the power, 2015-10-30 01:48:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1419293003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1419293003/60001

[commit-bot: I haz the power, 2015-10-30 02:48:20]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-10-30 02:49:35]

Patchset 4 (id:??) landed as
https://crrev.com/48799d724056efafd4bc7faa6e77459fbd1efad0
Cr-Commit-Position: refs/heads/master@{#357034}