Update mojo sdk to rev f6c8ec07c01deebc13178d516225fd12695c3dc2

mojo/public/cpp/utility/tests/mutex_unittest.cc

Index: mojo/public/cpp/utility/tests/mutex_unittest.cc
diff --git a/mojo/public/cpp/utility/tests/mutex_unittest.cc b/mojo/public/cpp/utility/tests/mutex_unittest.cc
index d6f75da574a0dbfdb25c62cc8d6e9ad86581d8c5..78e95c532c51ff2cb818994e976a10c59ec0c0fe 100644
--- a/mojo/public/cpp/utility/tests/mutex_unittest.cc
+++ b/mojo/public/cpp/utility/tests/mutex_unittest.cc
@@ -90,7 +90,7 @@ class Fiddler {
       0,  // Seconds.
       (rand() % 10) * kNanosPerMilli // Nanoseconds.
     };
-    int rv = nanosleep(&req, NULL);
+    int rv = nanosleep(&req, nullptr);
     MOJO_ALLOW_UNUSED_LOCAL(rv);
     assert(rv == 0);
   }