Simplify flattening to just write enough to call the factory

src/effects/SkXfermodeImageFilter.cpp

 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkXfermodeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkDevice.h"
@@ skipping 13 matching lines @@
                                              SkImageFilter* inputs[2],
                                              const CropRect* cropRect)
   : INHERITED(2, inputs, cropRect), fMode(mode) {
     SkSafeRef(fMode);
 }
 
 SkXfermodeImageFilter::~SkXfermodeImageFilter() {
     SkSafeUnref(fMode);
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkXfermodeImageFilter::SkXfermodeImageFilter(SkReadBuffer& buffer)
   : INHERITED(2, buffer) {
     fMode = buffer.readXfermode();
 }
+#endif
+
+SkFlattenable* SkXfermodeImageFilter::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 2);
+    return Create(buffer.readXfermode(), common.inputAt(0), common.inputAt(1), &common.cropRect());
+}
 
 void SkXfermodeImageFilter::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeFlattenable(fMode);
 }
 
 bool SkXfermodeImageFilter::onFilterImage(Proxy* proxy,
                                             const SkBitmap& src,
                                             const Context& ctx,
                                             SkBitmap* dst,
@@ skipping 110 matching lines @@
     paint.addColorEffect(xferEffect)->unref();
     context->drawRect(paint, srcRect);
 
     offset->fX = backgroundOffset.fX;
     offset->fY = backgroundOffset.fY;
     WrapTexture(dst, src.width(), src.height(), result);
     return true;
 }
 
 #endif