Finish conversion to sk_sp<SkShader>

example/HelloWorld.cpp

Index: example/HelloWorld.cpp
diff --git a/example/HelloWorld.cpp b/example/HelloWorld.cpp
index e13cb3b438045ef777ca711b471081b1981bdf4f..e30c4674e8d89a6e752fa96831fd07c90cf94cb7 100644
--- a/example/HelloWorld.cpp
+++ b/example/HelloWorld.cpp
@@ -93,10 +93,7 @@ void HelloWorldWindow::drawContents(SkCanvas* canvas) {
     paint.setColor(SK_ColorRED);
 
     // Draw a rectangle with red paint
-    SkRect rect = {
-            10, 10,
-            128, 128
-    };
+    SkRect rect = SkRect::MakeXYWH(10, 10, 128, 128);
     canvas->drawRect(rect, paint);
 
     // Set up a linear gradient and draw a circle
@@ -107,18 +104,15 @@ void HelloWorldWindow::drawContents(SkCanvas* canvas) {
         };
         SkColor linearColors[] = {SK_ColorGREEN, SK_ColorBLACK};
 
-        SkShader* shader = SkGradientShader::CreateLinear(
-                linearPoints, linearColors, NULL, 2,
-                SkShader::kMirror_TileMode);
-        SkAutoUnref shader_deleter(shader);
-
-        paint.setShader(shader);
+        paint.setShader(SkGradientShader::MakeLinear(
+                linearPoints, linearColors, nullptr, 2,
+                SkShader::kMirror_TileMode));
         paint.setFlags(SkPaint::kAntiAlias_Flag);
 
         canvas->drawCircle(200, 200, 64, paint);
 
         // Detach shader
-        paint.setShader(NULL);
+        paint.setShader(nullptr);
     }
 
     // Draw a message with a nice black paint.