These tests stress pathops by describing the union of circle-like paths that have tiny line segments embedded and double back to create near-coincident conditions.

The fixes include
- detect when finding the active top loops between two possible answers
- preflight chasing winding to ensure answer is consistent
- binary search more often when quadratic intersection fails
- add more failure paths when an intersect is missed

While this fixes the chrome bug, reenabling path ops in svg should be deferred until additional fixes are landed.

TBR=
BUG=421132

Committed: https://skia.googlesource.com/skia/+/6f726addf3178b01949bb389ef83cf14a1d7b6b2

Review URL: https://codereview.chromium.org/633393002

1 files changed, 6 insertions, 3 deletions

diff --git a/src/pathops/SkOpContour.h b/src/pathops/SkOpContour.h
index 899367ab0e..7a1cc09247 100644
--- a/src/pathops/SkOpContour.h
+++ b/src/pathops/SkOpContour.h
@@ -127,9 +127,9 @@ public:
         }
     }
 
-    void checkEnds() {
+    bool checkEnds() {
         if (!fContainsCurves) {
-            return;
+            return true;
         }
         int segmentCount = fSegments.count();
         for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
@@ -140,8 +140,11 @@ public:
             if (segment->done()) {
                 continue;   // likely coincident, nothing to do
             }
-            segment->checkEnds();
+            if (!segment->checkEnds()) {
+                return false;
+            }
         }
+        return true;
     }
 
     void checkMultiples() {