switch xfermodes over to sk_sp

src/core/SkReadBuffer.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 SkReadBuffer_DEFINED
 #define SkReadBuffer_DEFINED
 
@@ skipping 127 matching lines @@
     }
     SkImageFilter* readImageFilter() { return this->readFlattenable<SkImageFilter>(); }
     SkMaskFilter*  readMaskFilter()  { return this->readFlattenable<SkMaskFilter>(); }
     sk_sp<SkPathEffect> readPathEffect()  {
         return sk_sp<SkPathEffect>(this->readFlattenable<SkPathEffect>());
     }
     sk_sp<SkRasterizer> readRasterizer() {
         return sk_sp<SkRasterizer>(this->readFlattenable<SkRasterizer>());
     }
     sk_sp<SkShader> readShader()     { return sk_sp<SkShader>(this->readFlattenable<SkShader>()); }
-    SkXfermode*    readXfermode()    { return this->readFlattenable<SkXfermode>(); }
+    sk_sp<SkXfermode> readXfermode() {
+        return sk_sp<SkXfermode>(this->readFlattenable<SkXfermode>());
+    }
 
     /**
      *  Like readFlattenable() but explicitly just skips the data that was written for the
      *  flattenable (or the sentinel that there wasn't one).
      */
     virtual void skipFlattenable();
 
     // binary data and arrays
     virtual bool readByteArray(void* value, size_t size);
     virtual bool readColorArray(SkColor* colors, size_t size);
@@ skipping 90 matching lines @@
     SkPicture::InstallPixelRefProc fBitmapDecoder;
 
 #ifdef DEBUG_NON_DETERMINISTIC_ASSERT
     // Debugging counter to keep track of how many bitmaps we
     // have decoded.
     int fDecodedBitmapIndex;
 #endif // DEBUG_NON_DETERMINISTIC_ASSERT
 };
 
 #endif // SkReadBuffer_DEFINED