Fix video_decoder GM

Change-Id: Ib0ecfa45ecbc9421f7c0fe1ae62af7b008c49580
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/363097
Reviewed-by: Florin Malita <fmalita@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>

gm/video_decoder.cpp

@@ -51,7 +51,7 @@ protected:
             if (0) {
                 SkDebugf("ts %g\n", timeStamp);
             }
-            canvas->drawImage(img, 10, 10, nullptr);
+            canvas->drawImage(img, 10, 10);
         }
     }