Propagate validation errors

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
 
 #include "SkPictureFlat.h"  // for DrawType
 
 class SkBitmap;
 class SkCanvas;
 class SkPaint;
 class SkPictureData;
 
 // The basic picture playback class replays the provided picture into a canvas.
 class SkPicturePlayback final : SkNoncopyable {
 public:
     SkPicturePlayback(const SkPictureData* data)
         : fPictureData(data)
         , fCurOffset(0) {
     }
 
-    void draw(SkCanvas* canvas, SkPicture::AbortCallback*, const SkReadBuffer* buffer);
+    void draw(SkCanvas* canvas, SkPicture::AbortCallback*, SkReadBuffer* buffer);
 
     // TODO: remove the curOp calls after cleaning up GrGatherDevice
     // Return the ID of the operation currently being executed when playing
     // back. 0 indicates no call is active.
     size_t curOpID() const { return fCurOffset; }
     void resetOpID() { fCurOffset = 0; }
 
 protected:
     const SkPictureData* fPictureData;
 
@@ skipping 19 matching lines @@
 
     private:
         SkPicturePlayback* fPlayback;
     };
 
 private:
     typedef SkNoncopyable INHERITED;
 };
 
 #endif