partial switch over to sp usage of shaders

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1776973003

Review URL: https://codereview.chromium.org/1776973003
diff --git a/gm/clippedbitmapshaders.cpp b/gm/clippedbitmapshaders.cpp
index 6225abe..4b77aba 100644
--- a/gm/clippedbitmapshaders.cpp
+++ b/gm/clippedbitmapshaders.cpp
@@ -82,11 +82,8 @@
         s.reset();
         s.setScale(8, 8);
         s.postTranslate(SLIDE_SIZE / 2, SLIDE_SIZE / 2);
-        SkShader* shader = SkShader::CreateBitmapShader(
-                bmp, fMode, fMode, &s);
-
         SkPaint paint;
-        paint.setShader(shader)->unref();
+        paint.setShader(SkShader::MakeBitmapShader(bmp, fMode, fMode, &s));
 
         if (fHQ) {
             paint.setFilterQuality(kHigh_SkFilterQuality);