Fix quad convexity with only one backward dir

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2465253008

Review-Url: https://codereview.chromium.org/2465253008

1 files changed, 3 insertions, 2 deletions

diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index 4dc2f96656..c1b6327193 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -2405,8 +2405,9 @@ private:
                 break;
             case kBackwards_DirChange:
                 if (fIsCurve) {
-                    fConvexity = SkPath::kConcave_Convexity;
-                    fFirstDirection = SkPathPriv::kUnknown_FirstDirection;
+                    // If any of the subsequent dir is non-backward, it'll be concave.
+                    // Otherwise, it's still convex.
+                    fExpectedDir = dir;
                 }
                 fLastVec = vec;
                 break;