add helper makeShader for the common Clamp case

Bug: skia:
Change-Id: I22cac56f35fed16daede0cf1b3e34dfa6f5ae3ea
Reviewed-on: https://skia-review.googlesource.com/14625
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/tests/FlattenableFactoryToName.cpp b/tests/FlattenableFactoryToName.cpp
index 35ec984..fc47dfc 100644
--- a/tests/FlattenableFactoryToName.cpp
+++ b/tests/FlattenableFactoryToName.cpp
@@ -37,6 +37,5 @@
     bm.allocN32Pixels(8, 8);
     bm.eraseColor(SK_ColorCYAN);
     sk_sp<SkImage> image(SkImage::MakeFromBitmap(bm));
-    auto shader = image->makeShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
-    test_flattenable(r, shader.get(), "SkImage::newShader()");
+    test_flattenable(r, image->makeShader().get(), "SkImage::newShader()");
 }