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

Review URL: https://codereview.chromium.org/1316233002
diff --git a/gm/tilemodes.cpp b/gm/tilemodes.cpp
index 4e4a2ff..26b8348 100644
--- a/gm/tilemodes.cpp
+++ b/gm/tilemodes.cpp
@@ -171,14 +171,14 @@
     int index = (int)ty;
     switch (index % 3) {
         case 0:
-            return SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors), tx);
+            return SkGradientShader::CreateLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors), tx);
         case 1:
-            return SkGradientShader::CreateRadial(center, rad, colors, NULL, SK_ARRAY_COUNT(colors), tx);
+            return SkGradientShader::CreateRadial(center, rad, colors, nullptr, SK_ARRAY_COUNT(colors), tx);
         case 2:
-            return SkGradientShader::CreateSweep(center.fX, center.fY, colors, NULL, SK_ARRAY_COUNT(colors));
+            return SkGradientShader::CreateSweep(center.fX, center.fY, colors, nullptr, SK_ARRAY_COUNT(colors));
     }
 
-    return NULL;
+    return nullptr;
 }
 
 typedef SkShader* (*ShaderProc)(SkShader::TileMode, SkShader::TileMode);