ipc: Move AttachmentBrokerPrivileged singleton logic into ipc/.

ipc: Move AttachmentBrokerPrivileged singleton logic into ipc/.

Previously, the logic was only used by ChildProcessHostImpl, so it lived there.
The logic actually needs to be invoked by both ChildProcessHostImpl, and
RenderProcessHostImpl, so I moved the logic into ipc/.

On Mac, the PortProvider needs to be passed to the AttachmentBrokerPrivileged
once, so I added a parameter to the constructor to do just that.

BUG=535711
Committed: https://crrev.com/d8a3d902c0914bb6a903348578ee7eaca90006d4
Cr-Commit-Position: refs/heads/master@{#355625}

[erikchen, 2015-10-21 20:02:07]

erikchen@chromium.org changed reviewers:
+ avi@chromium.org, tsepez@chromium.org

[erikchen, 2015-10-21 20:02:07]

tsepez: Please review ipc/
avi: Please review content/

[Tom Sepez, 2015-10-21 20:07:38]

https://codereview.chromium.org/1414603003/diff/1/ipc/attachment_broker_privi...
File ipc/attachment_broker_privileged.cc (right):

https://codereview.chromium.org/1414603003/diff/1/ipc/attachment_broker_privi...
ipc/attachment_broker_privileged.cc:45: // sets it as the global broker.
Can't lazy instance take care of this for us?

[erikchen, 2015-10-21 21:54:41]

tsepez: PTAL

https://codereview.chromium.org/1414603003/diff/1/ipc/attachment_broker_privi...
File ipc/attachment_broker_privileged.cc (right):

https://codereview.chromium.org/1414603003/diff/1/ipc/attachment_broker_privi...
ipc/attachment_broker_privileged.cc:45: // sets it as the global broker.
On 2015/10/21 20:07:38, Tom Sepez wrote:
> Can't lazy instance take care of this for us?

I do use a LazyInstance - I updated the comment to use the word LazyInstance
instead of singleton.

[Avi (use Gerrit), 2015-10-21 23:49:57]

lgtm

[erikchen, 2015-10-22 00:18:37]

avi, tsepez: PTAL

I expanded this CL to also include the plumbing for PortProvider.

[Avi (use Gerrit), 2015-10-22 01:04:24]

lgtm

OK

[Tom Sepez, 2015-10-22 17:43:21]

lgtm

[erikchen, 2015-10-22 17:49:47]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-10-22 17:50:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1414603003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1414603003/60001

[commit-bot: I haz the power, 2015-10-22 20:02:09]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-10-22 20:03:48]

Patchset 4 (id:??) landed as
https://crrev.com/d8a3d902c0914bb6a903348578ee7eaca90006d4
Cr-Commit-Position: refs/heads/master@{#355625}