fix pathops skp-derived bugs; add more failing tests

src/pathops/SkOpContour.cpp

 /*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 #include "SkIntersections.h"
 #include "SkOpContour.h"
 #include "SkPathWriter.h"
 #include "SkTSort.h"
@@ skipping 434 matching lines @@
         addTo2->addTPair(missingT2, addOther2, otherT2, false, missingPt2);
     } else {
         SkASSERT(minTIndex >= 0);
         missingPt2 = refSegment->span(maxTIndex).fPt;
     }
     if (!partial) {
         return;
     }
     if (cancelers) {
         if (missingT1 >= 0) {
+            if (addTo1->reversePoints(missingPt1, missingPt2)) {
+                SkTSwap(missingPt1, missingPt2);
+            }
             addTo1->addTCancel(missingPt1, missingPt2, addOther1);
         } else {
+            if (addTo2->reversePoints(missingPt1, missingPt2)) {
+                SkTSwap(missingPt1, missingPt2);
+            }
             addTo2->addTCancel(missingPt1, missingPt2, addOther2);
         }
     } else if (missingT1 >= 0) {
         addTo1->addTCoincident(missingPt1, missingPt2, addTo1 == addTo2 ? missingT2 : otherT2,
                 addOther1);
     } else {
         addTo2->addTCoincident(missingPt2, missingPt1, addTo2 == addTo1 ? missingT1 : otherT1,
                 addOther2);
     }
 }
@@ skipping 274 matching lines @@
         SkDebugf("%s empty contour\n", __FUNCTION__);
         SkASSERT(0);
         // FIXME: delete empty contour?
         return;
     }
     fBounds = fSegments.front().bounds();
     for (int index = 1; index < count; ++index) {
         fBounds.add(fSegments[index].bounds());
     }
 }