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:
R=mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/481513004
10 files changed