Define NDEBUG instead of SK_DEBUG/SK_RELEASE.

Define NDEBUG instead of SK_DEBUG/SK_RELEASE.

This makes our builds more like Chrome's, and will make our builds fail
if we accidentally use if SK_DEBUG instead of ifdef SK_DEBUG.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/753b870c62bd22cee3d9a15efc634822724084ac

[mtklein, 2014-08-20 13:35:10]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-08-20 13:36:01]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/481513004/1

[commit-bot: I haz the power, 2014-08-20 13:36:01]

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 a valid reviewer till 2014-08-20 19:36 UTC

[reed1, 2014-08-20 14:36:49]

lgtm

[commit-bot: I haz the power, 2014-08-20 14:38:53]

Committed patchset #1 (1) as 753b870c62bd22cee3d9a15efc634822724084ac