Revert of allow one zero length dash (patchset #8 id:140001 of https://codereview.chromium.org/1805963002/ )

Reason for revert:
Causes the dash bench to crash.

Example crash:
https://build.chromium.org/p/client.skia/builders/Perf-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release/builds/5581/steps/nanobench/logs/stdio

Original issue's description:
> allow one zero length dash
>
> If the constructed stroke that represents a dash has a
> single dash of length zero, and the end cap is square or
> round, draw the cap.
>
> The old code initialized the initial dash length to zero,
> making it ambiguous whether the first length is zero or
> not.
>
> R=robertphillips@google.com
> BUG=583299
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1805963002
>
> Committed: https://skia.googlesource.com/skia/+/5e1a24808415df2748822e8082e21a361362cdfe

TBR=robertphillips@google.com,reed@google.com,caryclark@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=583299

Review URL: https://codereview.chromium.org/1808303004

1 files changed, 8 insertions, 3 deletions

diff --git a/tests/DashPathEffectTest.cpp b/tests/DashPathEffectTest.cpp
index fa2395ef75..68fce9a142 100644
--- a/tests/DashPathEffectTest.cpp
+++ b/tests/DashPathEffectTest.cpp
@@ -12,15 +12,20 @@
 #include "SkStrokeRec.h"
 
 // crbug.com/348821 was rooted in SkDashPathEffect refusing to flatten and unflatten itself when
-// the effect is nonsense.  Here we test that it fails when passed nonsense parameters.
+// fInitialDashLength < 0 (a signal the effect is nonsense).  Here we test that it flattens.
 
 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 a nonsense effect.
+    SkScalar phase = SK_ScalarInfinity;  // Used to force the bad fInitialDashLength = -1 path.
     SkAutoTUnref<SkPathEffect> dash(SkDashPathEffect::Create(intervals, count, phase));
 
-    REPORTER_ASSERT(r, dash == nullptr);
+    // 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.
 }
 
 // Test out the asPoint culling behavior.