Simplify flattening to just write enough to call the factory

src/effects/SkArithmeticMode.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkArithmeticMode.h"
 #include "SkColorPriv.h"
 #include "SkReadBuffer.h"
@@ skipping 29 matching lines @@
 
 private:
     SkArithmeticMode_scalar(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4, bool enforcePMColor) {
         fK[0] = k1;
         fK[1] = k2;
         fK[2] = k3;
         fK[3] = k4;
         fEnforcePMColor = enforcePMColor;
     }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
     SkArithmeticMode_scalar(SkReadBuffer& buffer) : INHERITED(buffer) {
         fK[0] = buffer.readScalar();
         fK[1] = buffer.readScalar();
         fK[2] = buffer.readScalar();
         fK[3] = buffer.readScalar();
         fEnforcePMColor = buffer.readBool();
     }
+#endif
 
     virtual void flatten(SkWriteBuffer& buffer) const SK_OVERRIDE {
-        INHERITED::flatten(buffer);
         buffer.writeScalar(fK[0]);
         buffer.writeScalar(fK[1]);
         buffer.writeScalar(fK[2]);
         buffer.writeScalar(fK[3]);
         buffer.writeBool(fEnforcePMColor);
     }
     SkScalar fK[4];
     bool fEnforcePMColor;
 
+    friend class SkArithmeticMode;
+
     typedef SkXfermode INHERITED;
 };
 
+SkFlattenable* SkArithmeticMode_scalar::CreateProc(SkReadBuffer& buffer) {
+    const SkScalar k1 = buffer.readScalar();
+    const SkScalar k2 = buffer.readScalar();
+    const SkScalar k3 = buffer.readScalar();
+    const SkScalar k4 = buffer.readScalar();
+    const bool enforcePMColor = buffer.readBool();
+    return Create(k1, k2, k3, k4, enforcePMColor);
+}
+
 static int pinToByte(int value) {
     if (value < 0) {
         value = 0;
     } else if (value > 255) {
         value = 255;
     }
     return value;
 }
 
 static int arith(SkScalar k1, SkScalar k2, SkScalar k3, SkScalar k4,
@@ skipping 354 matching lines @@
                                              background);
     }
     return true;
 }
 
 #endif
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkArithmeticMode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkArithmeticMode_scalar)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END