Account for hairlines in quick rejection logic

bug:8531373
Change-Id: I35444014f23fc61da687694fccc0d13bce718793
diff --git a/libs/hwui/PathTessellator.cpp b/libs/hwui/PathTessellator.cpp
index 395bbf6..0879b1b 100644
--- a/libs/hwui/PathTessellator.cpp
+++ b/libs/hwui/PathTessellator.cpp
@@ -61,6 +61,7 @@
         bool forceExpand) {
     if (forceExpand || paint->getStyle() != SkPaint::kFill_Style) {
         float outset = paint->getStrokeWidth() * 0.5f;
+        if (outset == 0) outset = 0.5f; // account for hairline
         bounds.outset(outset, outset);
     }
 }