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

Review URL: https://codereview.chromium.org/1316233002
diff --git a/tools/CopyTilesRenderer.cpp b/tools/CopyTilesRenderer.cpp
index bc1e32e..f5ffb25 100644
--- a/tools/CopyTilesRenderer.cpp
+++ b/tools/CopyTilesRenderer.cpp
@@ -32,7 +32,7 @@
                                  bool useChecksumBasedFilenames, bool useMultiPictureDraw) {
         // Do not call INHERITED::init(), which would create a (potentially large) canvas which is
         // not used by bench_pictures.
-        SkASSERT(pict != NULL);
+        SkASSERT(pict != nullptr);
         // Only work with absolute widths (as opposed to percentages).
         SkASSERT(this->getTileWidth() != 0 && this->getTileHeight() != 0);
         fPicture.reset(pict)->ref();