ipc: Remove unnecessary attachment broker plumbing.

ipc: Remove unnecessary attachment broker plumbing.

The original design was to pass around an instance of an attachment broker. The
new design uses a single global, and no longer needs any plumbing. This CL
removes the last vestiges of the plumbing.

BUG=493414
Committed: https://crrev.com/30dc2811d9c106d733cea51f5600875cacba2f80
Cr-Commit-Position: refs/heads/master@{#350471}

[erikchen, 2015-09-19 01:07:13]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-19 01:07:23]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/1

[commit-bot: I haz the power, 2015-09-19 01:35:42]

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

[commit-bot: I haz the power, 2015-09-19 01:35:43]

Dry run: Try jobs failed on following builders:
  win8_chromium_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_ng/...)

[erikchen, 2015-09-19 01:50:33]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-19 01:51:12]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/20001

[commit-bot: I haz the power, 2015-09-19 02:24:41]

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

[commit-bot: I haz the power, 2015-09-19 02:24:41]

Dry run: Try jobs failed on following builders:
  win_chromium_compile_dbg_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)

[erikchen, 2015-09-22 19:24:41]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-22 19:24:59]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/60001

[commit-bot: I haz the power, 2015-09-22 20:30:31]

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

[commit-bot: I haz the power, 2015-09-22 20:30:32]

Dry run: Try jobs failed on following builders:
  win_chromium_compile_dbg_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)

[erikchen, 2015-09-22 20:55:22]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-22 20:56:32]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/80001

[commit-bot: I haz the power, 2015-09-22 21:21:51]

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

[commit-bot: I haz the power, 2015-09-22 21:21:52]

Dry run: Try jobs failed on following builders:
  win8_chromium_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_ng/...)

[erikchen, 2015-09-22 21:31:23]

The CQ bit was checked by erikchen@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-22 21:37:02]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/80001

[erikchen, 2015-09-22 21:59:52]

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

[erikchen, 2015-09-22 21:59:53]

tsepez: Please review.

[Tom Sepez, 2015-09-22 22:19:56]

LGTM on code deletion.

[erikchen, 2015-09-22 23:14:56]

erikchen@chromium.org changed reviewers:
+ avi@chromium.org, garykac@chromium.org, scottbyer@chromium.org

[erikchen, 2015-09-22 23:14:57]

garykac: Looking for a remoting/ review.
avi: Looking for a content/ review.
scottbyer: Looking for a cloud_print/ review.

[commit-bot: I haz the power, 2015-09-22 23:23:18]

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

[commit-bot: I haz the power, 2015-09-22 23:23:19]

Dry run: This issue passed the CQ dry run.

[Avi (use Gerrit), 2015-09-22 23:56:22]

lgtm

[Scott Byer, 2015-09-23 21:44:06]

LGTM for cloud print

[garykac, 2015-09-24 01:16:57]

chromoting lgtm

[erikchen, 2015-09-24 01:18:07]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-24 01:35:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1354973006/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1354973006/80001

[commit-bot: I haz the power, 2015-09-24 03:26:58]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-09-24 03:28:40]

Patchset 5 (id:??) landed as
https://crrev.com/30dc2811d9c106d733cea51f5600875cacba2f80
Cr-Commit-Position: refs/heads/master@{#350471}