fix some pathops bugs found in 1M skps

src/pathops/SkIntersections.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkIntersections_DEFINE
 #define SkIntersections_DEFINE
 
 #include "SkPathOpsConic.h"
 #include "SkPathOpsCubic.h"
 #include "SkPathOpsLine.h"
 #include "SkPathOpsPoint.h"
 #include "SkPathOpsQuad.h"
 
 class SkIntersections {
 public:
     SkIntersections()
         : fSwap(0)
 #ifdef SK_DEBUG
         , fDepth(0)
 #endif
     {
         sk_bzero(fPt, sizeof(fPt));
         sk_bzero(fPt2, sizeof(fPt2));
         sk_bzero(fT, sizeof(fT));
         sk_bzero(fNearlySame, sizeof(fNearlySame));
+#if DEBUG_T_SECT_LOOP_COUNT
+        sk_bzero(fDebugLoopCount, sizeof(fDebugLoopCount));
+#endif
         reset();
         fMax = 0;  // require that the caller set the max
     }
 
     class TArray {
     public:
         explicit TArray(const double ts[10]) : fTArray(ts) {}
         double operator[](int n) const {
             return fTArray[n];
         }
@@ skipping 232 matching lines @@
     static int VerticalIntercept(const SkDConic& conic, SkScalar x, double* roots);
 
     int depth() const {
 #ifdef SK_DEBUG
         return fDepth;
 #else
         return 0;
 #endif
     }
 
+    enum DebugLoop {
+        kIterations_DebugLoop,
+        kCoinCheck_DebugLoop,
+        kComputePerp_DebugLoop,
+    };
+
+    void debugBumpLoopCount(DebugLoop );
     int debugCoincidentUsed() const;
+    int debugLoopCount(DebugLoop ) const;
+    void debugResetLoopCount();
     void dump() const;  // implemented for testing only
 
 private:
     bool cubicCheckCoincidence(const SkDCubic& c1, const SkDCubic& c2);
     bool cubicExactEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2);
     void cubicNearEnd(const SkDCubic& cubic1, bool start, const SkDCubic& cubic2, const SkDRect& );
     void cleanUpParallelLines(bool parallel);
     void computePoints(const SkDLine& line, int used);
 
     SkDPoint fPt[12];  // FIXME: since scans store points as SkPoint, this should also
     SkDPoint fPt2[2];  // used by nearly same to store alternate intersection point
     double fT[2][12];
     uint16_t fIsCoincident[2];  // bit set for each curve's coincident T
     bool fNearlySame[2];  // true if end points nearly match
     unsigned char fUsed;
     unsigned char fMax;
     bool fAllowNear;
     bool fSwap;
 #ifdef SK_DEBUG
     int fDepth;
 #endif
+#if DEBUG_T_SECT_LOOP_COUNT
+    int fDebugLoopCount[3];
+#endif
 };
 
 #endif