Simplify flattening to just write enough to call the factory

src/effects/SkDisplacementMapEffect.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 "SkDisplacementMapEffect.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
@@ skipping 156 matching lines @@
   : INHERITED(2, inputs, cropRect)
   , fXChannelSelector(xChannelSelector)
   , fYChannelSelector(yChannelSelector)
   , fScale(scale)
 {
 }
 
 SkDisplacementMapEffect::~SkDisplacementMapEffect() {
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkDisplacementMapEffect::SkDisplacementMapEffect(SkReadBuffer& buffer)
   : INHERITED(2, buffer)
 {
     fXChannelSelector = (SkDisplacementMapEffect::ChannelSelectorType) buffer.readInt();
     fYChannelSelector = (SkDisplacementMapEffect::ChannelSelectorType) buffer.readInt();
     fScale            = buffer.readScalar();
     buffer.validate(channel_selector_type_is_valid(fXChannelSelector) &&
                     channel_selector_type_is_valid(fYChannelSelector) &&
                     SkScalarIsFinite(fScale));
 }
+#endif
+
+SkFlattenable* SkDisplacementMapEffect::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(2);
+    ChannelSelectorType xsel = (ChannelSelectorType)buffer.readInt();
+    ChannelSelectorType ysel = (ChannelSelectorType)buffer.readInt();
+    SkScalar scale = buffer.readScalar();
+    return Create(xsel, ysel, scale, common.inputAt(0), common.inputAt(1), &common.cropRect());
+}
 
 void SkDisplacementMapEffect::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeInt((int) fXChannelSelector);
     buffer.writeInt((int) fYChannelSelector);
     buffer.writeScalar(fScale);
 }
 
 bool SkDisplacementMapEffect::onFilterImage(Proxy* proxy,
                                             const SkBitmap& src,
@@ skipping 410 matching lines @@
                                        const GrGLCaps&, GrEffectKeyBuilder* b) {
     const GrDisplacementMapEffect& displacementMap =
         drawEffect.castEffect<GrDisplacementMapEffect>();
 
     uint32_t xKey = displacementMap.xChannelSelector();
     uint32_t yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 
     b->add32(xKey | yKey);
 }
 #endif