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

Review URL: https://codereview.chromium.org/1316233002
diff --git a/samplecode/SampleHairModes.cpp b/samplecode/SampleHairModes.cpp
index 8788577..ae41aa9 100644
--- a/samplecode/SampleHairModes.cpp
+++ b/samplecode/SampleHairModes.cpp
@@ -110,7 +110,7 @@
                 SkXfermode* mode = SkXfermode::Create(gModes[i].fMode);
 
                 canvas->drawRect(bounds, fBGPaint);
-                canvas->saveLayer(&bounds, NULL);
+                canvas->saveLayer(&bounds, nullptr);
                 SkScalar dy = drawCell(canvas, mode,
                                        gAlphaValue[alpha & 1],
                                        gAlphaValue[alpha & 2]);