allow one zero length dash

tests/DashPathEffectTest.cpp

Index: tests/DashPathEffectTest.cpp
diff --git a/tests/DashPathEffectTest.cpp b/tests/DashPathEffectTest.cpp
index 68fce9a142504bb9b5748674b7805756ad0d466f..fa2395ef7585668258374dbea51b08ed3772df36 100644
--- a/tests/DashPathEffectTest.cpp
+++ b/tests/DashPathEffectTest.cpp
@@ -12,20 +12,15 @@
 #include "SkStrokeRec.h"
 
 // crbug.com/348821 was rooted in SkDashPathEffect refusing to flatten and unflatten itself when
-// fInitialDashLength < 0 (a signal the effect is nonsense).  Here we test that it flattens.
+// the effect is nonsense.  Here we test that it fails when passed nonsense parameters.
 
 DEF_TEST(DashPathEffectTest_crbug_348821, r) {
     SkScalar intervals[] = { 1.76934361e+36f, 2.80259693e-45f };  // Values from bug.
     const int count = 2;
-    SkScalar phase = SK_ScalarInfinity;  // Used to force the bad fInitialDashLength = -1 path.
+    SkScalar phase = SK_ScalarInfinity;  // Used to force a nonsense effect.
     SkAutoTUnref<SkPathEffect> dash(SkDashPathEffect::Create(intervals, count, phase));
 
-    // nullptr -> refuses to work with flattening framework.
-    REPORTER_ASSERT(r, dash->getFactory() != nullptr);
-
-    SkWriteBuffer buffer;
-    buffer.writeFlattenable(dash);
-    REPORTER_ASSERT(r, buffer.bytesWritten() > 12);  // We'd write 12 if broken, >=40 if not.
+    REPORTER_ASSERT(r, dash == nullptr);
 }
 
 // Test out the asPoint culling behavior.