Fix size calcuation in video_decoder_resource.cc

Fix size calcuation in video_decoder_resource.cc

VideoDecoderResource::VideoDecoderResource() is only clearing 1/4 of
the decode_ids_ array, because the type of the array is uint32_t, and
we're passing the number of elements, not number of bytes.

BUG=469182
Committed: https://crrev.com/e9faf30f4261a10fb0f964fa91d8822acebd53e0
Cr-Commit-Position: refs/heads/master@{#321698}

[Tom Sepez, 2015-03-20 22:27:29]

tsepez@chromium.org changed reviewers:
+ bbudge@chromium.org, piman@chromium.org

[Tom Sepez, 2015-03-20 22:28:08]

Bill, review as original author.
piman for owners stamp.

[bbudge, 2015-03-20 22:31:17]

Thanks! LGTM

[Tom Sepez, 2015-03-20 23:59:21]

tsepez@chromium.org changed reviewers:
- piman@chromium.org

[Tom Sepez, 2015-03-20 23:59:58]

Actually, bbudge@ is an OWNER one directory up.  Removing piman.

[Tom Sepez, 2015-03-21 00:00:02]

The CQ bit was checked by tsepez@chromium.org

[commit-bot: I haz the power, 2015-03-21 00:02:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1021053005/1

[bbudge, 2015-03-21 00:06:31]

On 2015/03/20 23:59:58, Tom Sepez wrote:
> Actually, bbudge@ is an OWNER one directory up.  Removing piman.

Can I be cc'ed on the bug?

[commit-bot: I haz the power, 2015-03-21 07:48:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-21 07:49:13]

Patchset 1 (id:??) landed as
https://crrev.com/e9faf30f4261a10fb0f964fa91d8822acebd53e0
Cr-Commit-Position: refs/heads/master@{#321698}

[piman, 2015-03-23 20:19:28]

piman@chromium.org changed reviewers:
+ piman@chromium.org

[piman, 2015-03-23 20:19:29]

lgtm