win: Move DXVAVideoDecodeAccelerator's WeakPtrFactory member to the end.

win: Move DXVAVideoDecodeAccelerator's WeakPtrFactory member to the end.

Also fix initialization of weak_ptr_ which I had unintentionally broken in
https://codereview.chromium.org/1103713003

BUG=303818, 467287
Committed: https://crrev.com/3b97c2fbfb7f2d6854d98659eebfdadbf272a0c7
Cr-Commit-Position: refs/heads/master@{#327366}

[Nico, 2015-04-28 20:21:20]

thakis@chromium.org changed reviewers:
+ avi@chromium.org, dmichael@chromium.org

[dmichael (off chromium), 2015-04-28 20:24:53]

d'oh, sorry I missed weak_ptr_ in the last review. I thought I looked for that
kind of problem.

lgtm

[Avi (use Gerrit), 2015-04-28 20:35:28]

lgtm

[Nico, 2015-04-28 20:37:41]

On 2015/04/28 20:24:53, dmichael (off chromium) wrote:
> d'oh, sorry I missed weak_ptr_ in the last review. I thought I looked for that
> kind of problem.

(I looked for it to and tried to exclude this file from that patch, but
apparently I only reverted the changes to the .h, not the .cc, when I sent it
:-/)

[Nico, 2015-04-28 20:37:43]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-04-28 20:38:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1111903002/20001

[commit-bot: I haz the power, 2015-04-28 21:38:30]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-28 21:40:05]

Patchset 2 (id:??) landed as
https://crrev.com/3b97c2fbfb7f2d6854d98659eebfdadbf272a0c7
Cr-Commit-Position: refs/heads/master@{#327366}