partial switch over to sp usage of shaders

gm/colormatrix.cpp

Index: gm/colormatrix.cpp
diff --git a/gm/colormatrix.cpp b/gm/colormatrix.cpp
index b466188c6a063c484a2899d6dc4ca3121508155f..b6e83d3ceb9a2a0f270eee7679ab8c0b4c53864f 100644
--- a/gm/colormatrix.cpp
+++ b/gm/colormatrix.cpp
@@ -67,8 +67,8 @@ protected:
         SkPoint pts[] = {{0, 0}, {SkIntToScalar(width), SkIntToScalar(height)}};
         SkColor colors[] = {0x00000000, 0xFFFFFFFF};
         SkPaint paint;
-        paint.setShader(SkGradientShader::CreateLinear(pts, colors, nullptr, 2,
-                                                       SkShader::kClamp_TileMode))->unref();
+        paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
+                                                     SkShader::kClamp_TileMode));
         canvas.drawRect(SkRect::MakeWH(SkIntToScalar(width), SkIntToScalar(height)), paint);
         return SkImage::NewFromBitmap(bm);
     }