Use correct HRTF elevation response for negative elevations.

Use correct HRTF elevation response for negative elevations.

The computed index for negative elevations was off by one. When the
elevation is -45 deg, the selected response corresponded to the entry
for 90 deg, not 315 deg.

To simplify things, we just use a short table to map the index to the
(positive) elevation angle.

No tests for this, but see crbug.com/411191.
BUG=412442
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181986

[Raymond Toy, 2014-09-12 22:36:16]

rtoy@chromium.org changed reviewers:
+ kbr@chromium.org

[Raymond Toy, 2014-09-12 22:36:16]

PTAL.

[Ken Russell (switch to Gerrit), 2014-09-13 19:59:50]

LGTM

Would be good to add a test for this.

[Raymond Toy, 2014-09-15 16:25:48]

On 2014/09/13 19:59:50, Ken Russell wrote:
> LGTM
> 
> Would be good to add a test for this.

Thanks. Tests will get added in crbug.com/411191.

[Raymond Toy, 2014-09-15 16:26:17]

The CQ bit was checked by rtoy@chromium.org

[commit-bot: I haz the power, 2014-09-15 16:27:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/565303003/1

[commit-bot: I haz the power, 2014-09-15 17:27:47]

Committed patchset #1 (id:1) as 181986