Revert "Revert "Revert "Revert "Revert "Revert "Redefine the meaning of sample counts in GPU backend.""""""

This reverts commit 3a2cc2c2ec124de36d2544b2a523ef1dd317ca32.

Fix code with samplecnt=0 that slipped in between trybots/CQ and landing of previous version

Change-Id: Iab19f2e8d1e9901601c8c76244d7a88c5d707fab
Reviewed-on: https://skia-review.googlesource.com/103181
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index db1e064..157a484 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -350,7 +350,7 @@
     bool serial() const override { return !fThreaded; }
     const char* fileExtension() const override { return "png"; }
     SinkFlags flags() const override {
-        SinkFlags::Multisampled ms = fSampleCount > 0 ? SinkFlags::kMultisampled
+        SinkFlags::Multisampled ms = fSampleCount > 1 ? SinkFlags::kMultisampled
                                                       : SinkFlags::kNotMultisampled;
         return SinkFlags{ SinkFlags::kGPU, SinkFlags::kDirect, ms };
     }