Support serialization in SkRecord-backed SkPictures.

dm/DMSKPTask.h

Index: dm/DMSKPTask.h
diff --git a/dm/DMSKPTask.h b/dm/DMSKPTask.h
index ef465af06aae3c7efbcec6abf826a1ac6e8fb276..b8a288e037bc3154b8958e2b240e5e33fd39a637 100644
--- a/dm/DMSKPTask.h
+++ b/dm/DMSKPTask.h
@@ -14,14 +14,14 @@ namespace DM {
 
 class SKPTask : public CpuTask {
 public:
-    SKPTask(Reporter*, TaskRunner*, SkPicture*, SkString name);
+    SKPTask(Reporter*, TaskRunner*, const SkPicture*, SkString name);
 
     virtual void draw() SK_OVERRIDE;
     virtual bool shouldSkip() const SK_OVERRIDE { return false; }
     virtual SkString name() const SK_OVERRIDE { return fName; }
 
 private:
-    SkAutoTUnref<SkPicture> fPicture;
+    SkAutoTUnref<const SkPicture> fPicture;
     const SkString fName;
 };