Fix effect mapping computation for displacement-map w/ negative scale

Fix effect mapping computation for displacement-map w/ negative scale

When scale is negative, the displacement will be in the opposite
direction. Hence we need to only use the magnitude of the scale when
computing the effect of the filter.

BUG=641854
Committed: https://crrev.com/b5be3c886b80b2a7b0db0714e2ae1a1cb154bf3d
Cr-Commit-Position: refs/heads/master@{#420396}

[fs, 2016-09-22 14:57:44]

The CQ bit was checked by fs@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-09-22 14:57:58]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-22 16:20:25]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-22 16:20:26]

Dry run: This issue passed the CQ dry run.

[fs, 2016-09-22 17:11:45]

fs@opera.com changed reviewers:
+ pdr@chromium.org, senorblanco@chromium.org

[Stephen White, 2016-09-22 17:30:24]

LGTM

[fs, 2016-09-22 17:53:52]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2016-09-22 17:54:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-22 18:07:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-22 18:09:59]

Description was changed from

==========
Fix effect mapping computation for displacement-map w/ negative scale

When scale is negative, the displacement will be in the opposite
direction. Hence we need to only use the magnitude of the scale when
computing the effect of the filter.

BUG=641854
==========

to

==========
Fix effect mapping computation for displacement-map w/ negative scale

When scale is negative, the displacement will be in the opposite
direction. Hence we need to only use the magnitude of the scale when
computing the effect of the filter.

BUG=641854

Committed: https://crrev.com/b5be3c886b80b2a7b0db0714e2ae1a1cb154bf3d
Cr-Commit-Position: refs/heads/master@{#420396}
==========

[commit-bot: I haz the power, 2016-09-22 18:10:00]

Patchset 1 (id:??) landed as
https://crrev.com/b5be3c886b80b2a7b0db0714e2ae1a1cb154bf3d
Cr-Commit-Position: refs/heads/master@{#420396}