[Sk4fGradient] Use infinity floats for clamp-mode extreme positions
In clamp mode, we use a couple of synthetic edges that are supposed to
extend to +/- infinity (-inf .. P0 and Pn .. inf). Currently we use
SK_ScalarMin/Max, but these can be overrun with large/malicious inputs.
Use SK_ScalarInfinity/SK_ScalarNegativeInfinity instead, and tweak
compute_interval_props() to handle inf values gracefully.
BUG=skia:5835
R=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2441733002
Review-Url: https://chromiumcodereview.appspot.com/2441733002
2 files changed