Convert UtilityProcessHost to bootstrap Mojo Channel using the Shell connection

Convert UtilityProcessHost to bootstrap Mojo Channel using the Shell connection

R=rockot@chromium.org
BUG=

[Ben Goodger (Google), 2016-06-30 06:02:13]

On 2016/06/29 22:17:02, Ben Goodger (Google) wrote:

I still have one outstanding test that I'm going to have to discuss with you -
extension_unittests SandboxedUnpacker*.

First I had to convert it to a browsertest so there'd be enough Shell for it to
work.
Now I'm encountering all manner of thread restriction woe (not reflected in CL
as shown here).

[Ben Goodger (Google), 2016-06-30 14:30:48]

On 2016/06/30 06:02:13, Ben Goodger (Google) wrote:
> On 2016/06/29 22:17:02, Ben Goodger (Google) wrote:
> 
> I still have one outstanding test that I'm going to have to discuss with you -
> extension_unittests SandboxedUnpacker*.
> 
> First I had to convert it to a browsertest so there'd be enough Shell for it
to
> work.
> Now I'm encountering all manner of thread restriction woe (not reflected in CL
> as shown here).

Ahhhhh... managed to fix it as a unit_test. Phew.

[Ben Goodger (Google), 2016-06-30 14:40:43]

On 2016/06/30 14:30:48, Ben Goodger (Google) wrote:
> On 2016/06/30 06:02:13, Ben Goodger (Google) wrote:
> > On 2016/06/29 22:17:02, Ben Goodger (Google) wrote:
> > 
> > I still have one outstanding test that I'm going to have to discuss with you
-
> > extension_unittests SandboxedUnpacker*.
> > 
> > First I had to convert it to a browsertest so there'd be enough Shell for it
> to
> > work.
> > Now I'm encountering all manner of thread restriction woe (not reflected in
CL
> > as shown here).
> 
> Ahhhhh... managed to fix it as a unit_test. Phew.

OK this should be good to go.
Ken: PTAL

[Ken Rockot(use gerrit already), 2016-06-30 14:50:53]

LGTM

I was going to complain that it's kind of unclear as a casual reader why these
tests would have to create a ShellContext, but then I noticed that
InProcessUtilityThreadHelper is used in exactly the same way, i.e. it needs to
exist because reasons.

https://codereview.chromium.org/2112543002/diff/140001/content/browser/mojo/m...
File content/browser/mojo/mojo_shell_context.h (right):

https://codereview.chromium.org/2112543002/diff/140001/content/browser/mojo/m...
content/browser/mojo/mojo_shell_context.h:32: class CONTENT_EXPORT
MojoShellContext : public ShellContext {
nit: I suppose ShellContextImpl is a much better name for this naow. But I'd
consider it a TODO rather than a blocker.

[Ben Goodger (Google), 2016-06-30 15:24:52]

The CQ bit was checked by ben@chromium.org

[Ben Goodger (Google), 2016-06-30 15:24:53]

The patchset sent to the CQ was uploaded after l-g-t-m from rockot@chromium.org
Link to the patchset: https://codereview.chromium.org/2112543002/#ps180001
(title: ".")

[commit-bot: I haz the power, 2016-06-30 15:25:04]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-30 16:06:56]

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

[commit-bot: I haz the power, 2016-06-30 16:06:56]

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