VP8Decoder: Drop references to reference frames earlier.

VP8Decoder: Drop references to reference frames earlier.

Drop references to reference frames before requesting new surfaces to
ensure we don't hold onto them while the Accelerator is changing resolution,
risking reusing a stale buffer.

BUG=chrome-os-partner:35539
TEST=Hangouts, vdatest

Committed: https://crrev.com/0f47fc976b37b54583a061b0628f994bf727ba30
Cr-Commit-Position: refs/heads/master@{#313679}

[Pawel Osciak, 2015-01-29 05:47:35]

posciak@chromium.org changed reviewers:
+ wuchengli@chromium.org

[wuchengli, 2015-01-29 08:03:57]

lgtm

[Pawel Osciak, 2015-01-29 08:05:01]

The CQ bit was checked by posciak@chromium.org

[commit-bot: I haz the power, 2015-01-29 08:05:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/880773009/1

[commit-bot: I haz the power, 2015-01-29 08:39:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-29 08:40:59]

Patchset 1 (id:??) landed as
https://crrev.com/0f47fc976b37b54583a061b0628f994bf727ba30
Cr-Commit-Position: refs/heads/master@{#313679}