check for bad params sent to discrete patheffect

src/effects/SkDiscretePathEffect.cpp

Index: src/effects/SkDiscretePathEffect.cpp
diff --git a/src/effects/SkDiscretePathEffect.cpp b/src/effects/SkDiscretePathEffect.cpp
index 5af6ab4ceb2962ca0a113f343afee9e8fedfb2dd..1c6039c842369b6ba4a614d776a5edbb8b2bf896 100644
--- a/src/effects/SkDiscretePathEffect.cpp
+++ b/src/effects/SkDiscretePathEffect.cpp
@@ -14,6 +14,12 @@
 
 sk_sp<SkPathEffect> SkDiscretePathEffect::Make(SkScalar segLength, SkScalar deviation,
                                                uint32_t seedAssist) {
+    if (!SkScalarIsFinite(segLength) || !SkScalarIsFinite(deviation)) {
+        return nullptr;
+    }
+    if (segLength <= SK_ScalarNearlyZero) {
+        return nullptr;
+    }
     return sk_sp<SkPathEffect>(new SkDiscretePathEffect(segLength, deviation, seedAssist));
 }