Split SkPicturePlayback out of SkPictureData

include/utils/SkPictureUtils.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPictureUtils_DEFINED
 #define SkPictureUtils_DEFINED
 
 #include "SkPicture.h"
 #include "SkTDArray.h"
 
 class SkData;
 struct SkRect;
 
 class SK_API SkPictureUtils {
 public:
     /**
      *  Given a rectangular visible "window" into the picture, return an array
      *  of SkPixelRefs that might intersect that area. To keep the call fast,
      *  the returned list is not guaranteed to be exact, so it may miss some,
      *  and it may return false positives.
      *
      *  The pixelrefs returned in the SkData are already owned by the picture,
      *  so the returned pointers are only valid while the picture is in scope
      *  and remains unchanged.
      */
-    static SkData* GatherPixelRefs(SkPicture* pict, const SkRect& area);
+    static SkData* GatherPixelRefs(const SkPicture* pict, const SkRect& area);
 
     /**
      * SkPixelRefContainer provides a base class for more elaborate pixel ref
      * query structures (e.g., rtrees, quad-trees, etc.)
      */
     class SkPixelRefContainer : public SkRefCnt {
     public:
         virtual void add(SkPixelRef* pr, const SkRect& rect) = 0;
 
         // The returned array may contain duplicates
@@ skipping 34 matching lines @@
     };
 
     /**
      *  Fill the provided pixel ref container with the picture's pixel ref
      *  and rect information.
      */
     static void GatherPixelRefsAndRects(SkPicture* pict, SkPixelRefContainer* prCont);
 };
 
 #endif