Simplify flattening to just write enough to call the factory

include/core/SkImageFilter.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageFilter_DEFINED
 #define SkImageFilter_DEFINED
 
@@ skipping 189 matching lines @@
     SK_DEFINE_FLATTENABLE_TYPE(SkImageFilter)
 
 protected:
     class Common {
     public:
         Common() {}
         ~Common();
 
         bool unflatten(SkReadBuffer&, int expectedInputs = -1);
 
-        CropRect        cropRect() const { return fCropRect; }
+        const CropRect& cropRect() const { return fCropRect; }
         int             inputCount() const { return fInputs.count(); }
         SkImageFilter** inputs() const { return fInputs.get(); }
 
         // If the caller wants a copy of the inputs, call this and it will transfer ownership
         // of the unflattened input filters to the caller. This is just a short-cut for copying
         // the inputs, calling ref() on each, and then waiting for Common's destructor to call
         // unref() on each.
         void detachInputs(SkImageFilter** inputs);
 
     private:
@@ skipping 10 matching lines @@
 
     /**
      *  Constructs a new SkImageFilter read from an SkReadBuffer object.
      *
      *  @param inputCount    The exact number of inputs expected for this SkImageFilter object.
      *                       -1 can be used if the filter accepts any number of inputs.
      *  @param rb            SkReadBuffer object from which the SkImageFilter is read.
      */
     explicit SkImageFilter(int inputCount, SkReadBuffer& rb);
 
-    virtual void flatten(SkWriteBuffer& wb) const SK_OVERRIDE;
+    void flattenCommon(SkWriteBuffer&) const;

[Stephen White, 2014/07/17 21:29:00]

Now that we have a flattenCommon(), would it make sense to move
Common:unflatten() to SkImageFilter::unflattenCommon() for symmetry? Might
require making Common's members public, but it basically is a struct already.
Just a thought.

 
     /**
      *  This is the virtual which should be overridden by the derived class
      *  to perform image filtering.
      *
      *  src is the original primitive bitmap. If the filter has a connected
      *  input, it should recurse on that input and use that in place of src.
      *
      *  The matrix is the current matrix on the canvas.
      *
@@ skipping 56 matching lines @@
                              const SkIRect& bounds) const;
 
 private:
     typedef SkFlattenable INHERITED;
     int fInputCount;
     SkImageFilter** fInputs;
     CropRect fCropRect;
 };
 
 #endif