Revert of pathops version two (patchset #16 id:150001 of https://codereview.chromium.org/1002693002/)

Reason for revert:
ASAN investigation

Original issue's description:
> pathops version two
>
> R=reed@google.com
>
> marked 'no commit' to attempt to get trybots to run
>
> TBR=reed@google.com
>
> Committed: https://skia.googlesource.com/skia/+/ccec0f958ffc71a9986d236bc2eb335cb2111119

TBR=caryclark@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1029993002

1 files changed, 72 insertions, 19 deletions

diff --git a/src/pathops/SkIntersectionHelper.h b/src/pathops/SkIntersectionHelper.h
index c633fd02df..3569c934de 100644
--- a/src/pathops/SkIntersectionHelper.h
+++ b/src/pathops/SkIntersectionHelper.h
@@ -5,7 +5,6 @@
  * found in the LICENSE file.
  */
 #include "SkOpContour.h"
-#include "SkOpSegment.h"
 #include "SkPath.h"
 
 #ifdef SK_DEBUG
@@ -22,9 +21,42 @@ public:
         kCubic_Segment = SkPath::kCubic_Verb,
     };
 
+    bool addCoincident(SkIntersectionHelper& other, const SkIntersections& ts, bool swap) {
+        return fContour->addCoincident(fIndex, other.fContour, other.fIndex, ts, swap);
+    }
+
+    // FIXME: does it make sense to write otherIndex now if we're going to
+    // fix it up later?
+    void addOtherT(int index, double otherT, int otherIndex) {
+        fContour->addOtherT(fIndex, index, otherT, otherIndex);
+    }
+
+    bool addPartialCoincident(SkIntersectionHelper& other, const SkIntersections& ts, int index,
+            bool swap) {
+        return fContour->addPartialCoincident(fIndex, other.fContour, other.fIndex, ts, index,
+                swap);
+    }
+
+    // Avoid collapsing t values that are close to the same since
+    // we walk ts to describe consecutive intersections. Since a pair of ts can
+    // be nearly equal, any problems caused by this should be taken care
+    // of later.
+    // On the edge or out of range values are negative; add 2 to get end
+    int addT(const SkIntersectionHelper& other, const SkPoint& pt, double newT) {
+        return fContour->addT(fIndex, other.fContour, other.fIndex, pt, newT);
+    }
+
+    int addSelfT(const SkPoint& pt, double newT) {
+        return fContour->addSelfT(fIndex, pt, newT);
+    }
+
     bool advance() {
-        fSegment = fSegment->next();
-        return fSegment != NULL;
+        return ++fIndex < fLast;
+    }
+
+    void alignTPt(SkIntersectionHelper& other, bool swap, int index,
+            SkIntersections* ts, SkPoint* point) {
+        fContour->alignTPt(fIndex, other.fContour, other.fIndex, swap, index, ts, point);
     }
 
     SkScalar bottom() const {
@@ -32,15 +64,30 @@ public:
     }
 
     const SkPathOpsBounds& bounds() const {
-        return fSegment->bounds();
+        return fContour->segments()[fIndex].bounds();
     }
 
-    SkOpContour* contour() const {
-        return fSegment->contour();
+    void init(SkOpContour* contour) {
+        fContour = contour;
+        fIndex = 0;
+        fLast = contour->segments().count();
     }
 
-    void init(SkOpContour* contour) {
-        fSegment = contour->first();
+    bool isAdjacent(const SkIntersectionHelper& next) {
+        return fContour == next.fContour && fIndex + 1 == next.fIndex;
+    }
+
+    bool isFirstLast(const SkIntersectionHelper& next) {
+        return fContour == next.fContour && fIndex == 0
+                && next.fIndex == fLast - 1;
+    }
+
+    bool isPartial(double t1, double t2, const SkDPoint& pt1, const SkDPoint& pt2) const {
+        const SkOpSegment& segment = fContour->segments()[fIndex];
+        double mid = (t1 + t2) / 2;
+        SkDPoint midPtByT = segment.dPtAtT(mid);
+        SkDPoint midPtByAvg = SkDPoint::Mid(pt1, pt2);
+        return midPtByT.approximatelyPEqual(midPtByAvg);
     }
 
     SkScalar left() const {
@@ -48,40 +95,41 @@ public:
     }
 
     const SkPoint* pts() const {
-        return fSegment->pts();
+        return fContour->segments()[fIndex].pts();
     }
 
     SkScalar right() const {
         return bounds().fRight;
     }
 
-    SkOpSegment* segment() const {
-        return fSegment;
-    }
-
     SegmentType segmentType() const {
-        SegmentType type = (SegmentType) fSegment->verb();
+        const SkOpSegment& segment = fContour->segments()[fIndex];
+        SegmentType type = (SegmentType) segment.verb();
         if (type != kLine_Segment) {
             return type;
         }
-        if (fSegment->isHorizontal()) {
+        if (segment.isHorizontal()) {
             return kHorizontalLine_Segment;
         }
-        if (fSegment->isVertical()) {
+        if (segment.isVertical()) {
             return kVerticalLine_Segment;
         }
         return kLine_Segment;
     }
 
     bool startAfter(const SkIntersectionHelper& after) {
-        fSegment = after.fSegment->next();
-        return fSegment != NULL;
+        fIndex = after.fIndex;
+        return advance();
     }
 
     SkScalar top() const {
         return bounds().fTop;
     }
 
+    SkPath::Verb verb() const {
+        return fContour->segments()[fIndex].verb();
+    }
+
     SkScalar x() const {
         return bounds().fLeft;
     }
@@ -99,5 +147,10 @@ public:
     }
 
 private:
-    SkOpSegment* fSegment;
+    // utility callable by the user from the debugger when the implementation code is linked in
+    void dump() const;
+
+    SkOpContour* fContour;
+    int fIndex;
+    int fLast;
 };