Send SkPicture deletion message lazily.

include/core/SkPicture.h

 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPicture_DEFINED
 #define SkPicture_DEFINED
@@ skipping 118 matching lines @@
     void playback(SkCanvas* canvas, AbortCallback* = NULL) const;
 
     /** Return the cull rect used when creating this picture: { 0, 0, cullWidth, cullHeight }.
         It does not necessarily reflect the bounds of what has been recorded into the picture.
         @return the cull rect used to create this picture
     */
     SkRect cullRect() const { return fCullRect; }
 
     /** Return a non-zero, unique value representing the picture.
      */
-    uint32_t uniqueID() const { return fUniqueID; }
+    uint32_t uniqueID() const;
 
     /**
      *  Serialize to a stream. If non NULL, serializer will be used to serialize
      *  any bitmaps in the picture.
      *
      *  TODO: Use serializer to serialize SkImages as well.
      */
     void serialize(SkWStream*, SkPixelSerializer* serializer = NULL) const;
 
     /**
@@ skipping 106 matching lines @@
     static bool IsValidPictInfo(const SkPictInfo& info);
 
     // Takes ownership of the SkRecord and (optional) SnapshotArray, refs the (optional) BBH.
     SkPicture(const SkRect& cullRect, SkRecord*, SnapshotArray*, SkBBoxHierarchy*);
 
     static SkPicture* Forwardport(const SkPictInfo&, const SkPictureData*);
     static SkPictureData* Backport(const SkRecord&, const SkPictInfo&,
                                    SkPicture const* const drawablePics[], int drawableCount);
 
     // uint32_t fRefCnt; from SkNVRefCnt<SkPicture>
-    const uint32_t                        fUniqueID;
+    mutable uint32_t                      fUniqueID;
     const SkRect                          fCullRect;
     mutable SkAutoTUnref<const AccelData> fAccelData;
     SkAutoTUnref<const SkRecord>          fRecord;
     SkAutoTUnref<const SkBBoxHierarchy>   fBBH;
     SkAutoTDelete<const SnapshotArray>    fDrawablePicts;
 
     // helpers for fDrawablePicts
     int drawableCount() const;
     // will return NULL if drawableCount() returns 0
     SkPicture const* const* drawablePicts() const;
@@ skipping 17 matching lines @@
 
     friend class SkPictureRecorder;            // SkRecord-based constructor.
     friend class GrLayerHoister;               // access to fRecord
     friend class ReplaceDraw;
     friend class SkPictureUtils;
     friend class SkRecordedDrawable;
 };
 SK_COMPILE_ASSERT(sizeof(SkPicture) <= 96, SkPictureSize);
 
 #endif