Simplify flattening to just write enough to call the factory

src/effects/SkAlphaThresholdFilter.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 "SkAlphaThresholdFilter.h"
 #include "SkBitmap.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkRegion.h"
 
 class SK_API SkAlphaThresholdFilterImpl : public SkImageFilter {
 public:
     SkAlphaThresholdFilterImpl(const SkRegion& region, SkScalar innerThreshold,
                                SkScalar outerThreshold, SkImageFilter* input);
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkAlphaThresholdFilterImpl)
 
 protected:
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
     explicit SkAlphaThresholdFilterImpl(SkReadBuffer& buffer);
+#endif
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
 
     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
                                SkBitmap* result, SkIPoint* offset) const SK_OVERRIDE;
 #if SK_SUPPORT_GPU
     virtual bool asNewEffect(GrEffect** effect, GrTexture* texture,
                              const SkMatrix& matrix, const SkIRect& bounds) const SK_OVERRIDE;
 #endif
 
 private:
@@ skipping 193 matching lines @@
     if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
         GrPixelConfigIsOpaque(this->texture(0)->config())) {
         *validFlags = kA_GrColorComponentFlag;
     } else {
         *validFlags = 0;
     }
 }
 
 #endif
 
+#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(SkReadBuffer& buffer)
   : INHERITED(1, buffer) {
     fInnerThreshold = buffer.readScalar();
     fOuterThreshold = buffer.readScalar();
     buffer.readRegion(&fRegion);
 }
+#endif
+
+SkFlattenable* SkAlphaThresholdFilterImpl::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
+    SkScalar inner = buffer.readScalar();
+    SkScalar outer = buffer.readScalar();
+    SkRegion rgn;
+    buffer.readRegion(&rgn);
+    return SkAlphaThresholdFilter::Create(rgn, inner, outer, common.inputAt(0));
+}
 
 SkAlphaThresholdFilterImpl::SkAlphaThresholdFilterImpl(const SkRegion& region,
                                                        SkScalar innerThreshold,
                                                        SkScalar outerThreshold,
                                                        SkImageFilter* input)
     : INHERITED(1, &input)
     , fRegion(region)
     , fInnerThreshold(innerThreshold)
     , fOuterThreshold(outerThreshold) {
 }
@@ skipping 108 matching lines @@
                                                   (U8CPU)(SkColorGetG(source) * scale),
                                                   (U8CPU)(SkColorGetB(source) * scale));
                 }
             }
             dptr[y * dst->width() + x] = output_color;
         }
     }
 
     return true;
 }