Update bench to be able to preprocess skps

include/core/SkDevice.h

Index: include/core/SkDevice.h
===================================================================
--- include/core/SkDevice.h	(revision 14136)
+++ include/core/SkDevice.h	(working copy)
@@ -345,6 +345,13 @@
 
     /**
      *  PRIVATE / EXPERIMENTAL -- do not call
+     *  Purge all discardable optimization information for 'picture'. If
+     *  picture is NULL then purge discardable information for all pictures.
+     */
+    virtual void EXPERIMENTAL_purge(SkPicture* picture);
+
+    /**
+     *  PRIVATE / EXPERIMENTAL -- do not call
      *  This entry point gives the backend an opportunity to take over the rendering
      *  of 'picture'. If optimization data is available (due to an earlier
      *  'optimize' call) this entry point should make use of it and return true
@@ -353,7 +360,7 @@
      *  to perform some device-specific warm up tasks and then let SkCanvas
      *  perform the main rendering loop (by return false from here).
      */
-    virtual bool EXPERIMENTAL_drawPicture(SkPicture* picture);
+    virtual bool EXPERIMENTAL_drawPicture(SkCanvas* canvas, SkPicture* picture);
 
 private:
     friend class SkCanvas;