improve cull, so we don't create empty segments

BUG=skia:3224

Review URL: https://codereview.chromium.org/798093002
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
index f866ea0..8cd703f 100644
--- a/src/effects/SkDashPathEffect.cpp
+++ b/src/effects/SkDashPathEffect.cpp
@@ -94,7 +94,7 @@
         }
 
         SkASSERT(minX < maxX);
-        if (maxX < bounds.fLeft || minX > bounds.fRight) {
+        if (maxX <= bounds.fLeft || minX >= bounds.fRight) {
             return false;
         }
 
@@ -125,7 +125,7 @@
         }
 
         SkASSERT(minY < maxY);
-        if (maxY < bounds.fTop || minY > bounds.fBottom) {
+        if (maxY <= bounds.fTop || minY >= bounds.fBottom) {
             return false;
         }