Implement SkPicture::bytesUsed() for SkRecord backend

include/utils/SkPictureUtils.h

Index: include/utils/SkPictureUtils.h
diff --git a/include/utils/SkPictureUtils.h b/include/utils/SkPictureUtils.h
index c35e1c74090996c8daf1f71f96b4966ef15f7616..9b060898fd7c835f390bf5684c2a465dbe50b44b 100644
--- a/include/utils/SkPictureUtils.h
+++ b/include/utils/SkPictureUtils.h
@@ -78,6 +78,14 @@ public:
      *  and rect information.
      */
     static void GatherPixelRefsAndRects(SkPicture* pict, SkPixelRefContainer* prCont);
+
+    /**
+     *  How many bytes are allocated to hold the SkPicture.
+     *  Includes operations, parameters, bounding data, deletion listeners;
+     *  does not include large objects that SkRecord holds a reference to
+     *  (e.g. paths, pixels backing bitmaps).

[mtklein, 2014/11/18 19:26:14]

Might add nested pictures to the list of things we don't count?  Took me a while
to remember that.

[tomhudson, 2014/11/18 19:35:12]

Done.

+     */
+    static size_t ApproximateBytesUsed(const SkPicture* pict);
 };
 
 #endif