Simplify flattening to just write enough to call the factory

src/effects/SkMatrixImageFilter.cpp

 /*
  * Copyright 2014 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 "SkMatrixImageFilter.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 11 matching lines @@
     fTransform(transform),
     fFilterLevel(filterLevel) {
 }
 
 SkMatrixImageFilter* SkMatrixImageFilter::Create(const SkMatrix& transform,
                                                  SkPaint::FilterLevel filterLevel,
                                                  SkImageFilter* input) {
     return SkNEW_ARGS(SkMatrixImageFilter, (transform, filterLevel, input));
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkMatrixImageFilter::SkMatrixImageFilter(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     buffer.readMatrix(&fTransform);
     fFilterLevel = static_cast<SkPaint::FilterLevel>(buffer.readInt());
 }
+#endif
+
+SkFlattenable* SkMatrixImageFilter::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(1);
+    SkMatrix matrix;
+    buffer.readMatrix(&matrix);
+    SkPaint::FilterLevel level = static_cast<SkPaint::FilterLevel>(buffer.readInt());
+    return Create(matrix, level, common.inputAt(0));
+}
 
 void SkMatrixImageFilter::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeMatrix(fTransform);
     buffer.writeInt(fFilterLevel);
 }
 
 SkMatrixImageFilter::~SkMatrixImageFilter() {
 }
 
@@ skipping 70 matching lines @@
     matrix.mapRect(&floatBounds, SkRect::Make(src));
     SkIRect bounds;
     floatBounds.roundOut(&bounds);
     if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
         return false;
     }
 
     *dst = bounds;
     return true;
 }