Reland #1 "ipc: Add a new field num_brokered_attachments to the message header."

Reland #1 "ipc: Add a new field num_brokered_attachments to the message header."

This otherwise innocuous CL is causing an unusual crash in Canary. At first
glance, the crash appears related to IPC, but further digging indicates that
it's probably related to corruption of a ResourceBuffer. I've updated that class
to use CHECKs instead of DCHECKs https://codereview.chromium.org/1325153002/.

I expect this CL to cause ~100 crashes in the next Chrome Canary. I intend to
revert this CL after a single Canary release. This CL will help me better
diagnose the exact nature of the crash.

BUG=493414
Committed: https://crrev.com/d32c32bef61d80f68208e550ace18f50f1c498d1
Cr-Commit-Position: refs/heads/master@{#347250}

[erikchen, 2015-09-03 01:28:49]

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

[erikchen, 2015-09-03 01:28:49]

tsepez: Please review.

[erikchen, 2015-09-03 19:08:24]

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

[erikchen, 2015-09-03 19:08:25]

avi: Please review content/

[Avi (use Gerrit), 2015-09-03 19:31:01]

lgtm

Crash ALL the canaries!

https://codereview.chromium.org/1330563002/diff/20001/content/child/resource_...
File content/child/resource_dispatcher.cc (right):

https://codereview.chromium.org/1330563002/diff/20001/content/child/resource_...
content/child/resource_dispatcher.cc:227: base::debug::Alias(buffer_size);
debug::Alias only works if you can download the minidumps and load them into a
debugger.

If that works for you, go for it. I much prefer crash keys.

[erikchen, 2015-09-03 19:39:42]

On 2015/09/03 19:31:01, Avi wrote:
> lgtm
> 
> Crash ALL the canaries!
> 
>
https://codereview.chromium.org/1330563002/diff/20001/content/child/resource_...
> File content/child/resource_dispatcher.cc (right):
> 
>
https://codereview.chromium.org/1330563002/diff/20001/content/child/resource_...
> content/child/resource_dispatcher.cc:227: base::debug::Alias(buffer_size);
> debug::Alias only works if you can download the minidumps and load them into a
> debugger.
> 
> If that works for you, go for it. I much prefer crash keys.

The minidumps have been working for me, and this particular variable gets
aliased out.

[Tom Sepez, 2015-09-03 19:41:17]

lgtm

[erikchen, 2015-09-03 19:48:44]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-09-03 19:49:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1330563002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1330563002/20001

[commit-bot: I haz the power, 2015-09-03 20:05:38]

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

[commit-bot: I haz the power, 2015-09-03 20:05:39]

Try jobs failed on following builders:
  android_compile_dbg on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_compile...)
  cast_shell_android on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_andr...)
  linux_chromium_gn_rel on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[erikchen, 2015-09-03 20:17:25]

The CQ bit was checked by erikchen@chromium.org

[erikchen, 2015-09-03 20:17:25]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org,
avi@chromium.org
Link to the patchset: https://codereview.chromium.org/1330563002/#ps60001
(title: "Rebase and add missing ampersand.")

[commit-bot: I haz the power, 2015-09-03 20:18:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1330563002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1330563002/60001

[commit-bot: I haz the power, 2015-09-03 21:41:21]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-09-03 21:41:57]

Patchset 4 (id:??) landed as
https://crrev.com/d32c32bef61d80f68208e550ace18f50f1c498d1
Cr-Commit-Position: refs/heads/master@{#347250}

[erikchen, 2015-09-04 16:56:40]

A revert of this CL (patchset #4 id:60001) has been created in
https://codereview.chromium.org/1314803005/ by erikchen@chromium.org.

The reason for reverting is: This CL was only ever intended to make it into one
Canary. .