Fix race in ShellConnectionRef

Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive (because
AddRef will never run), which is a problem. But it's
less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org

Committed: https://crrev.com/422c8bdec8d814af792916dbff086350a286c54f
Cr-Commit-Position: refs/heads/master@{#394049}

[Ken Rockot(use gerrit already), 2016-05-17 02:49:01]

Description was changed from

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the ShellClient (and thus
the factory) being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive, which is
a problem - but less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org
==========

to

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive, which is
a problem - but less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org
==========

[Ken Rockot(use gerrit already), 2016-05-17 02:49:32]

Description was changed from

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive, which is
a problem - but less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org
==========

to

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive (because
AddRef will never run), which is a problem. But it's
less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org
==========

[Ben Goodger (Google), 2016-05-17 03:09:31]

lgtm

[Ken Rockot(use gerrit already), 2016-05-17 03:12:01]

The CQ bit was checked by rockot@chromium.org

[commit-bot: I haz the power, 2016-05-17 03:12:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1987583002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1987583002/1

[commit-bot: I haz the power, 2016-05-17 04:37:06]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-17 04:39:35]

Description was changed from

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive (because
AddRef will never run), which is a problem. But it's
less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org
==========

to

==========
Fix race in ShellConnectionRef

When a ShellConnectionRef is Cloned it may post a task
to the factory's thread to add a ref. This can race with
the ref-count going to zero and the factory being deleted.

This CL changes ShellConnectionRef to hold a WeakPtr
to the factory to avoid the race.

This means it's possible for a ShellConnectionRef to be
acquired without keeping the ShellClient alive (because
AddRef will never run), which is a problem. But it's
less of a problem than crashing, for now.

BUG=612332
R=ben@chromium.org

Committed: https://crrev.com/422c8bdec8d814af792916dbff086350a286c54f
Cr-Commit-Position: refs/heads/master@{#394049}
==========

[commit-bot: I haz the power, 2016-05-17 04:39:36]

Patchset 1 (id:??) landed as
https://crrev.com/422c8bdec8d814af792916dbff086350a286c54f
Cr-Commit-Position: refs/heads/master@{#394049}