change SkAnnotation to not inherit from SkFlattenable (does not need dynamic factories)

include/core/SkAnnotation.h

Index: include/core/SkAnnotation.h
diff --git a/include/core/SkAnnotation.h b/include/core/SkAnnotation.h
index 83256ddb0e32161f218d031304e79f0938a26a6a..52e0e10976d53623149456b5fad9c14306e06d07 100644
--- a/include/core/SkAnnotation.h
+++ b/include/core/SkAnnotation.h
@@ -20,7 +20,7 @@ struct SkPoint;
  *  Experimental class for annotating draws. Do not use directly yet.
  *  Use helper functions at the bottom of this file for now.
  */
-class SkAnnotation : public SkFlattenable {
+class SkAnnotation : public SkRefCnt {
 public:
     enum Flags {
         // If set, the associated drawing primitive should not be drawn
@@ -39,11 +39,8 @@ public:
      */
     SkData* find(const char key[]) const;
 
-    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkAnnotation)
-
-protected:
     SkAnnotation(SkFlattenableReadBuffer&);
-    virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
+    void writeToBuffer(SkFlattenableWriteBuffer&) const;
 
 private:
     SkString    fKey;