SkImage method for detecting lazy decoding

src/lazy/SkCachingPixelRef.h

Index: src/lazy/SkCachingPixelRef.h
diff --git a/src/lazy/SkCachingPixelRef.h b/src/lazy/SkCachingPixelRef.h
index 25fde0a781bb8dd0a7c44e8cabddac32498ece37..818db22b19b5390f68d508bd1a270134161c626d 100644
--- a/src/lazy/SkCachingPixelRef.h
+++ b/src/lazy/SkCachingPixelRef.h
@@ -50,6 +50,8 @@ protected:
         return fImageGenerator->refEncodedData();
     }
 
+    bool onIsLazyGenerated() const override { return true; }
+
 private:
     SkImageGenerator* const fImageGenerator;
     bool                    fErrorInDecoding;