fix path op conic bugs

src/pathops/SkOpSpan.h

Index: src/pathops/SkOpSpan.h
diff --git a/src/pathops/SkOpSpan.h b/src/pathops/SkOpSpan.h
index dab0dfaf033ed163ae6d909c9f0aa6580f571ea3..e512554cc6f4c12e86ee1da8f60626307092514d 100644
--- a/src/pathops/SkOpSpan.h
+++ b/src/pathops/SkOpSpan.h
@@ -372,6 +372,14 @@ protected:  // no direct access to internals to avoid treating a span base as a
 
 class SkOpSpan : public SkOpSpanBase {
 public:
+    bool alreadyAdded() const {
+        if (fAlreadyAdded) {
+            return true;
+        }
+        fAlreadyAdded = true;
+        return false;
+    }
+
     bool clearCoincident() {
         SkASSERT(!final());
         if (fCoincident == this) {
@@ -506,6 +514,7 @@ private:  // no direct access to internals to avoid treating a span base as a sp
     int fOppValue;  // normally 0 -- when binary coincident edges combine, opp value goes here
     int fTopTTry; // specifies direction and t value to try next
     bool fDone;  // if set, this span to next higher T has been processed
+    mutable bool fAlreadyAdded;
 };
 
 #endif