IPC: Relax thread constraints on Channel-associated send

IPC: Relax thread constraints on Channel-associated send

This removes a DCHECK from ChannelAssociatedGroupController, allowing
messages to be sent from arbitrary threads rather than only from the
IO thread or proxy thread.

While it is still unsafe to bind associated endpoints on non-proxy
non-IO threads, this allows control messages to be transmitted
safely from any thread, so for example an AssociatedPtrInfo can safely
notify the request side of closure if it's destroyed on an arbitrary
thread.

BUG=663046
R=yzshen@chromium.org

Committed: https://crrev.com/becd3f741efe619c34bb569fd4ab18d85da45d6f
Cr-Commit-Position: refs/heads/master@{#430705}

[Ken Rockot(use gerrit already), 2016-11-07 23:03:57]

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

[commit-bot: I haz the power, 2016-11-07 23:04:57]

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

[Ken Rockot(use gerrit already), 2016-11-07 23:07:30]

PTAL. See the bug for context.

If someone accidentally uses a Channel-associated AssociatedInterfacePtr from an
invalid thread, this will make it harder to catch that nustaje. But it would
seem unfortunate to break the use case described in the bug just to keep the
DCHECK in place. WDYT?

[yzshen1, 2016-11-07 23:25:25]

lgtm

[Ken Rockot(use gerrit already), 2016-11-07 23:29:50]

The CQ bit was unchecked by rockot@chromium.org

[Ken Rockot(use gerrit already), 2016-11-07 23:29:51]

The CQ bit was checked by rockot@chromium.org

[commit-bot: I haz the power, 2016-11-07 23:30:05]

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, 2016-11-08 01:10:20]

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

[commit-bot: I haz the power, 2016-11-08 01:10:21]

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

[Ken Rockot(use gerrit already), 2016-11-08 20:41:49]

The CQ bit was checked by rockot@chromium.org

[commit-bot: I haz the power, 2016-11-08 20:42:32]

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, 2016-11-08 20:47:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-08 21:00:07]

Description was changed from

==========
IPC: Relax thread constraints on Channel-associated send

This removes a DCHECK from ChannelAssociatedGroupController, allowing
messages to be sent from arbitrary threads rather than only from the
IO thread or proxy thread.

While it is still unsafe to bind associated endpoints on non-proxy
non-IO threads, this allows control messages to be transmitted
safely from any thread, so for example an AssociatedPtrInfo can safely
notify the request side of closure if it's destroyed on an arbitrary
thread.

BUG=663046
R=yzshen@chromium.org
==========

to

==========
IPC: Relax thread constraints on Channel-associated send

This removes a DCHECK from ChannelAssociatedGroupController, allowing
messages to be sent from arbitrary threads rather than only from the
IO thread or proxy thread.

While it is still unsafe to bind associated endpoints on non-proxy
non-IO threads, this allows control messages to be transmitted
safely from any thread, so for example an AssociatedPtrInfo can safely
notify the request side of closure if it's destroyed on an arbitrary
thread.

BUG=663046
R=yzshen@chromium.org

Committed: https://crrev.com/becd3f741efe619c34bb569fd4ab18d85da45d6f
Cr-Commit-Position: refs/heads/master@{#430705}
==========

[commit-bot: I haz the power, 2016-11-08 21:00:08]

Patchset 1 (id:??) landed as
https://crrev.com/becd3f741efe619c34bb569fd4ab18d85da45d6f
Cr-Commit-Position: refs/heads/master@{#430705}