Fix ImageFilter fuzzer issue

src/core/SkPicturePlayback.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPicturePlayback_DEFINED
 #define SkPicturePlayback_DEFINED
 
@@ skipping 20 matching lines @@
     // back. 0 indicates no call is active.
     size_t curOpID() const { return fCurOffset; }
     void resetOpID() { fCurOffset = 0; }
 
 protected:
     const SkPictureData* fPictureData;
 
     // The offset of the current operation when within the draw method
     size_t fCurOffset;
 
-    void handleOp(SkReader32* reader,
+    void handleOp(SkReadBuffer* reader,
                   DrawType op,
                   uint32_t size,
                   SkCanvas* canvas,
                   const SkMatrix& initialMatrix);
 
-    static DrawType ReadOpAndSize(SkReader32* reader, uint32_t* size);
+    static DrawType ReadOpAndSize(SkReadBuffer* reader, uint32_t* size);
 
     class AutoResetOpID {
     public:
         AutoResetOpID(SkPicturePlayback* playback) : fPlayback(playback) { }
         ~AutoResetOpID() {
             if (fPlayback) {
                 fPlayback->resetOpID();
             }
         }
 
     private:
         SkPicturePlayback* fPlayback;
     };
 
 private:
     typedef SkNoncopyable INHERITED;
 };
 
 #endif