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

Review URL: https://codereview.chromium.org/1316233002
diff --git a/src/codec/SkMasks.cpp b/src/codec/SkMasks.cpp
index b136c59..b860314 100644
--- a/src/codec/SkMasks.cpp
+++ b/src/codec/SkMasks.cpp
@@ -139,7 +139,7 @@
     if (((masks.red & masks.green) | (masks.red & masks.blue) |
             (masks.red & masks.alpha) | (masks.green & masks.blue) |
             (masks.green & masks.alpha) | (masks.blue & masks.alpha)) != 0) {
-        return NULL;
+        return nullptr;
     }
 
     // Collect information about the masks