Simplify flattening to just write enough to call the factory

src/effects/SkOffsetImageFilter.cpp

 /*
  * Copyright 2012 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 "SkOffsetImageFilter.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 73 matching lines @@
     SkIRect bounds = src;
     bounds.offset(-SkScalarCeilToInt(vec.fX), -SkScalarCeilToInt(vec.fY));
     bounds.join(src);
     if (getInput(0)) {
         return getInput(0)->filterBounds(bounds, ctm, dst);
     }
     *dst = bounds;
     return true;
 }
 
+SkFlattenable* SkOffsetImageFilter::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(1);
+    SkPoint offset;
+    buffer.readPoint(&offset);
+    return Create(offset.x(), offset.y(), common.inputAt(0), &common.cropRect());
+}
+
 void SkOffsetImageFilter::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fOffset);
 }
 
 SkOffsetImageFilter::SkOffsetImageFilter(SkScalar dx, SkScalar dy, SkImageFilter* input,
                                          const CropRect* cropRect)
   : INHERITED(1, &input, cropRect) {
     fOffset.set(dx, dy);
 }
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkOffsetImageFilter::SkOffsetImageFilter(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     buffer.readPoint(&fOffset);
     buffer.validate(SkScalarIsFinite(fOffset.fX) &&
                     SkScalarIsFinite(fOffset.fY));
 }
+#endif