Add missing null check to AVDA deferred rendering shutdown path.

Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
Committed: https://crrev.com/426b349ca21fe6e023caf76f6a92deba79fd9525
Cr-Commit-Position: refs/heads/master@{#371324}

[liberato (no reviews please), 2016-01-25 18:50:29]

Description was changed from

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
==========

to

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
==========

[liberato (no reviews please), 2016-01-25 18:50:29]

liberato@chromium.org changed reviewers:
+ sandersd@chromium.org

[sandersd (OOO until July 31), 2016-01-25 18:59:30]

lgtm

[liberato (no reviews please), 2016-01-25 21:30:37]

The CQ bit was checked by liberato@chromium.org

[commit-bot: I haz the power, 2016-01-25 21:34:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1632793002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1632793002/20001

[commit-bot: I haz the power, 2016-01-25 21:47:04]

Description was changed from

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
==========

to

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
==========

[commit-bot: I haz the power, 2016-01-25 21:47:04]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-01-25 21:49:53]

Description was changed from

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335
==========

to

==========
Add missing null check to AVDA deferred rendering shutdown path.

If the GVD tears down AVDA before Initialize is called on the
strategy, usually due to an unsupported format, then the deferred
rendering backing strategy would access |shared_state_| before it
was initialized.

It now detects this, and skips all cleanup if Initialize wasn't
ever called.

BUG=580335

Committed: https://crrev.com/426b349ca21fe6e023caf76f6a92deba79fd9525
Cr-Commit-Position: refs/heads/master@{#371324}
==========

[commit-bot: I haz the power, 2016-01-25 21:49:54]

Patchset 2 (id:??) landed as
https://crrev.com/426b349ca21fe6e023caf76f6a92deba79fd9525
Cr-Commit-Position: refs/heads/master@{#371324}