Remove SK_SUPPORT_LEGACY_CONIC_COMPUTE_QUAD_POW2

Remove SK_SUPPORT_LEGACY_CONIC_COMPUTE_QUAD_POW2

The flag is no longer used in Chromium.

BUG=458898
R=reed@google.com,robertphillips@google.com

Committed: https://skia.googlesource.com/skia/+/d6f87b56d573b93a154156b948122b984da7e4b2

[f(malita), 2015-02-17 01:17:41]

The CQ bit was checked by fmalita@chromium.org

[commit-bot: I haz the power, 2015-02-17 01:18:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/931663004/1

[commit-bot: I haz the power, 2015-02-17 01:18:36]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-02-17 07:18 UTC

[commit-bot: I haz the power, 2015-02-17 07:18:36]

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

[commit-bot: I haz the power, 2015-02-17 07:18:36]

No LGTM from a valid reviewer yet. Please ask for an LGTM from a
full Skia committer from
https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

[robertphillips, 2015-02-17 17:18:17]

lgtm

[robertphillips, 2015-02-17 17:18:21]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2015-02-17 17:18:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/931663004/1

[commit-bot: I haz the power, 2015-02-17 17:18:37]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/d6f87b56d573b93a154156b948122b984da7e4b2