Style Change: NULL->nullptr
DOCS_PREVIEW= https://skia.org/?cl=1316233002

Review URL: https://codereview.chromium.org/1316233002
diff --git a/samplecode/SampleBitmapRect.cpp b/samplecode/SampleBitmapRect.cpp
index b39db4c..d7eed02 100644
--- a/samplecode/SampleBitmapRect.cpp
+++ b/samplecode/SampleBitmapRect.cpp
@@ -37,7 +37,7 @@
     paint.setAntiAlias(true);
     const SkPoint pts[] = { { 0, 0 }, { SCALAR_SIZE, SCALAR_SIZE } };
     const SkColor colors[] = { SK_ColorWHITE, SK_ColorBLUE };
-    paint.setShader(SkGradientShader::CreateLinear(pts, colors, NULL, 2,
+    paint.setShader(SkGradientShader::CreateLinear(pts, colors, nullptr, 2,
                                                    SkShader::kClamp_TileMode))->unref();
     canvas.drawCircle(SCALAR_SIZE/2, SCALAR_SIZE/2, SCALAR_SIZE/2, paint);
 }