Allow prolonged CanvasAsyncBlobCreator lifetime, avoid indirect leaks.

Allow prolonged CanvasAsyncBlobCreator lifetime, avoid indirect leaks.

Weakly keeping this async object to avoid resource leaks is problematic
(r399445 + r399675), as the object must remain alive until completed.

Undo that experiment and instead keep the object alive until all its
posted tasks have been processed. But for the task that wins and
is processed first, have it clear out the heap references that
would otherwise keep heavy objects alive.

R=
BUG=

Committed: https://crrev.com/ffd698c83520c7efa276decfe453b1a43eb2ab6b
Cr-Commit-Position: refs/heads/master@{#399856}

[sof, 2016-06-15 07:05:37]

sigbjornf@opera.com changed reviewers:
+ haraken@chromium.org

[sof, 2016-06-15 07:05:37]

please take a look.

The 'weak' experiment didn't pan out, back to explicit clearing of resources.
That CanvasAsynBlobCreator itself lives a bit longer is acceptable.

[haraken, 2016-06-15 07:09:35]

LGTM

[sof, 2016-06-15 07:18:56]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2016-06-15 07:19:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2065913003/1

[commit-bot: I haz the power, 2016-06-15 08:20:56]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-15 08:22:24]

Description was changed from

==========
Allow prolonged CanvasAsyncBlobCreator lifetime, avoid indirect leaks.

Weakly keeping this async object to avoid resource leaks is problematic
(r399445 + r399675), as the object must remain alive until completed.

Undo that experiment and instead keep the object alive until all its
posted tasks have been processed. But for the task that wins and
is processed first, have it clear out the heap references that
would otherwise keep heavy objects alive.

R=
BUG=
==========

to

==========
Allow prolonged CanvasAsyncBlobCreator lifetime, avoid indirect leaks.

Weakly keeping this async object to avoid resource leaks is problematic
(r399445 + r399675), as the object must remain alive until completed.

Undo that experiment and instead keep the object alive until all its
posted tasks have been processed. But for the task that wins and
is processed first, have it clear out the heap references that
would otherwise keep heavy objects alive.

R=
BUG=

Committed: https://crrev.com/ffd698c83520c7efa276decfe453b1a43eb2ab6b
Cr-Commit-Position: refs/heads/master@{#399856}
==========

[commit-bot: I haz the power, 2016-06-15 08:22:25]

Patchset 1 (id:??) landed as
https://crrev.com/ffd698c83520c7efa276decfe453b1a43eb2ab6b
Cr-Commit-Position: refs/heads/master@{#399856}