pathops coincidence and security rewrite

src/pathops/SkPathOpsPoint.h

Index: src/pathops/SkPathOpsPoint.h
diff --git a/src/pathops/SkPathOpsPoint.h b/src/pathops/SkPathOpsPoint.h
index e3f722bede18219384532a11c1975064304d730d..f30f155e8fc451afe1c6c593b1b06634b7ea585e 100644
--- a/src/pathops/SkPathOpsPoint.h
+++ b/src/pathops/SkPathOpsPoint.h
@@ -58,12 +58,20 @@ struct SkDVector {
     }
 
     // similar to cross, this bastardization considers nearly coincident to be zero
+    // uses ulps epsilon == 16
     double crossCheck(const SkDVector& a) const {
         double xy = fX * a.fY;
         double yx = fY * a.fX;
         return AlmostEqualUlps(xy, yx) ? 0 : xy - yx;
     }
 
+    // allow tinier numbers
+    double crossNoNormalCheck(const SkDVector& a) const {
+        double xy = fX * a.fY;
+        double yx = fY * a.fX;
+        return AlmostEqualUlpsNoNormalCheck(xy, yx) ? 0 : xy - yx;
+    }
+
     double dot(const SkDVector& a) const {
         return fX * a.fX + fY * a.fY;
     }
@@ -75,6 +83,12 @@ struct SkDVector {
     double lengthSquared() const {
         return fX * fX + fY * fY;
     }
+
+    void normalize() {
+        double inverseLength = 1 / this->length();
+        fX *= inverseLength;
+        fY *= inverseLength;
+    }
 };
 
 struct SkDPoint {
@@ -164,7 +178,7 @@ struct SkDPoint {
         float tiniest = SkTMin(SkTMin(SkTMin(a.fX, b.fX), a.fY), b.fY);
         float largest = SkTMax(SkTMax(SkTMax(a.fX, b.fX), a.fY), b.fY);
         largest = SkTMax(largest, -tiniest);
-        return AlmostPequalUlps((double) largest, largest + dist); // is dist within ULPS tolerance?
+        return AlmostDequalUlps((double) largest, largest + dist); // is dist within ULPS tolerance?
     }
 
     // only used by testing