return pictures as sk_sp

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1811703002

Review URL: https://codereview.chromium.org/1811703002
diff --git a/tests/PictureBBHTest.cpp b/tests/PictureBBHTest.cpp
index 0a0d3da..deb299a 100644
--- a/tests/PictureBBHTest.cpp
+++ b/tests/PictureBBHTest.cpp
@@ -45,7 +45,7 @@
                                                          SkIntToScalar(fPictureHeight),
                                                          factory);
         this->doTest(playbackCanvas, *recordCanvas);
-        SkAutoTUnref<SkPicture> picture(recorder.endRecording());
+        sk_sp<SkPicture> picture(recorder.finishRecordingAsPicture());
         playbackCanvas.drawPicture(picture);
         REPORTER_ASSERT(reporter, SK_ColorGREEN == fResultBitmap.getColor(0, 0));
     }