Fix memory leak in MultiPictureDraw GM

R=fmalita@google.com, fmalita@chromium.org

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/585033002
diff --git a/gm/multipicturedraw.cpp b/gm/multipicturedraw.cpp
index eeb5909..a915acd 100644
--- a/gm/multipicturedraw.cpp
+++ b/gm/multipicturedraw.cpp
@@ -407,7 +407,7 @@
         virtual void onOnceBeforeDraw() SK_OVERRIDE {
             fPictures[0] = make_hex_plane_picture(SK_ColorWHITE);
             fPictures[1] = make_hex_plane_picture(SK_ColorGRAY);
-            fPictures[2] = SkRef(make_sierpinski_picture());
+            fPictures[2] = make_sierpinski_picture();
         }
 
         virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {