ipc: Make a new class PlaceholderBrokerableAttachment.

ipc: Make a new class PlaceholderBrokerableAttachment.

Instances of this class need to be replaced before the message can be
dispatched. This mechanism is a lot cleaner than the previous mechanism, which
had an "unbrokered" state for every type of BrokerableAttachment, which had to
be mutated before being dispatched.

BUG=493414
Committed: https://crrev.com/87351da8166440ba0978a3c74701aa8242b72295
Cr-Commit-Position: refs/heads/master@{#348952}

[erikchen, 2015-08-28 21:15:24]

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

[commit-bot: I haz the power, 2015-08-28 21:16:14]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/1

[commit-bot: I haz the power, 2015-08-28 21:22:15]

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

[commit-bot: I haz the power, 2015-08-28 21:22:16]

Dry run: Try jobs failed on following builders:
  android_chromium_gn_compile_dbg on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  android_chromium_gn_compile_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)

[erikchen, 2015-08-28 21:29:11]

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

[commit-bot: I haz the power, 2015-08-28 21:29:39]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/20001

[commit-bot: I haz the power, 2015-08-28 22:04:41]

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

[commit-bot: I haz the power, 2015-08-28 22:04:41]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[erikchen, 2015-08-28 22:59:32]

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

[commit-bot: I haz the power, 2015-08-28 23:01:12]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/50025
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/50025

[commit-bot: I haz the power, 2015-08-28 23:35:24]

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

[commit-bot: I haz the power, 2015-08-28 23:35:25]

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...)
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[erikchen, 2015-08-29 00:25:48]

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

[commit-bot: I haz the power, 2015-08-29 00:26:35]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/70001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/70001

[erikchen, 2015-08-29 00:47:53]

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

[commit-bot: I haz the power, 2015-08-29 01:06:40]

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

[commit-bot: I haz the power, 2015-08-29 01:06:41]

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

[Tom Sepez, 2015-09-10 16:05:14]

lgtm

[erikchen, 2015-09-11 20:06:59]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-09-11 20:06:59]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org
Link to the patchset: https://codereview.chromium.org/1317093007/#ps90001
(title: "Rebase.")

[commit-bot: I haz the power, 2015-09-11 20:07:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/90001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/90001

[commit-bot: I haz the power, 2015-09-11 20:16:41]

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

[commit-bot: I haz the power, 2015-09-11 20:16:42]

Try jobs failed on following builders:
  ios_dbg_simulator_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)

[erikchen, 2015-09-11 21:16:14]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-09-11 21:16:15]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org
Link to the patchset: https://codereview.chromium.org/1317093007/#ps110001
(title: "Rebase errors.")

[commit-bot: I haz the power, 2015-09-11 21:17:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/110001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/110001

[commit-bot: I haz the power, 2015-09-11 21:31:49]

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

[commit-bot: I haz the power, 2015-09-11 21:31:50]

Try jobs failed on following builders:
  cast_shell_android on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_andr...)
  ios_dbg_simulator_ninja on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios_dbg_simulator...)

[erikchen, 2015-09-11 21:33:55]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-09-11 21:33:55]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org
Link to the patchset: https://codereview.chromium.org/1317093007/#ps130001
(title: "More rebase errors.")

[commit-bot: I haz the power, 2015-09-11 21:35:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-11 21:53:55]

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

[commit-bot: I haz the power, 2015-09-11 21:53:56]

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_...)

[erikchen, 2015-09-11 21:56:06]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-11 21:57:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-11 22:14:32]

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

[commit-bot: I haz the power, 2015-09-11 22:14:33]

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

[erikchen, 2015-09-11 22:30:49]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-11 22:31:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-11 22:57:58]

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

[commit-bot: I haz the power, 2015-09-11 22:57:59]

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

[erikchen, 2015-09-12 01:07:46]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-12 01:09:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-12 01:51:56]

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

[commit-bot: I haz the power, 2015-09-12 01:51:57]

Try jobs failed on following builders:
  linux_chromium_compile_dbg_32_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[erikchen, 2015-09-12 17:17:37]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-12 17:17:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-12 20:19:29]

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

[commit-bot: I haz the power, 2015-09-12 20:19:30]

Try jobs failed on following builders:
  linux_chromium_asan_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_compile_dbg_ng on tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_ozone_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_clobber_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_gn_chromeos_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[erikchen, 2015-09-13 17:50:14]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-13 17:51:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-13 23:52:55]

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

[commit-bot: I haz the power, 2015-09-13 23:52:55]

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

[erikchen, 2015-09-14 17:11:34]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-14 17:11:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-14 17:23:05]

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

[commit-bot: I haz the power, 2015-09-14 17:23:06]

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

[erikchen, 2015-09-14 19:22:15]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-09-14 19:22:15]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org
Link to the patchset: https://codereview.chromium.org/1317093007/#ps170001
(title: "Rebase errors.")

[commit-bot: I haz the power, 2015-09-14 19:22:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/170001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/170001

[commit-bot: I haz the power, 2015-09-14 19:59:01]

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

[commit-bot: I haz the power, 2015-09-14 19:59:01]

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/...)
  win_chromium_compile_dbg_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_comp...)

[erikchen, 2015-09-14 20:26:23]

Patchset #10 (id:170001) has been deleted

[erikchen, 2015-09-14 20:26:28]

Patchset #9 (id:150001) has been deleted

[erikchen, 2015-09-15 17:31:59]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-15 17:32:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317093007/130001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317093007/130001

[commit-bot: I haz the power, 2015-09-15 19:11:19]

Committed patchset #8 (id:130001)

[commit-bot: I haz the power, 2015-09-15 19:12:13]

Patchset 8 (id:??) landed as
https://crrev.com/87351da8166440ba0978a3c74701aa8242b72295
Cr-Commit-Position: refs/heads/master@{#348952}

[commit-bot: I haz the power, 2015-09-23 12:47:52]

Patchset 8 (id:??) landed as
https://crrev.com/87351da8166440ba0978a3c74701aa8242b72295
Cr-Commit-Position: refs/heads/master@{#348952}