Add a means of extracting active operations from SkPicture

include/core/SkPicture.h

Index: include/core/SkPicture.h
===================================================================
--- include/core/SkPicture.h	(revision 13766)
+++ include/core/SkPicture.h	(working copy)
@@ -13,6 +13,7 @@
 #include "SkBitmap.h"
 #include "SkImageDecoder.h"
 #include "SkRefCnt.h"
+#include "SkTDArray.h"
 
 class SkBBoxHierarchy;
 class SkCanvas;
@@ -148,6 +149,13 @@
     */
     void endRecording();
 
+    /** PRIVATE / EXPERIMENTAL -- do not call
+        Return the operations required to render the content inside
+        queryRect. A NULL return value means all the operations are needed.
+        A non-NULL but zero sized array means there is nothing to draw.
+    */
+    const SkTDArray<void*>* EXPERIMENTAL_getActiveOps(const SkIRect& queryRect);
+
     /** Replays the drawing commands on the specified canvas. This internally
         calls endRecording() if that has not already been called.
         @param canvas the canvas receiving the drawing commands.