Simplify flattening to just write enough to call the factory

samplecode/SampleAll.cpp

Index: samplecode/SampleAll.cpp
diff --git a/samplecode/SampleAll.cpp b/samplecode/SampleAll.cpp
index 92fe258dd6a4ed6652e68cc04ca3c1010162ef0f..395314c7ff0e2bfdaab285b0e9aa02339f3224a5 100644
--- a/samplecode/SampleAll.cpp
+++ b/samplecode/SampleAll.cpp
@@ -172,9 +172,11 @@ protected:
         dst->addCircle(loc.fX, loc.fY, fRadius);
     }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
     Dot2DPathEffect(SkReadBuffer& buffer) : INHERITED(buffer) {
         fRadius = buffer.readScalar();
     }
+#endif
     virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
         this->INHERITED::flatten(buffer);
         buffer.writeScalar(fRadius);