Mojo: NULL -> nullptr in mojo/public/cpp outside of bindings.

mojo/public/cpp/environment/lib/environment.cc

Index: mojo/public/cpp/environment/lib/environment.cc
diff --git a/mojo/public/cpp/environment/lib/environment.cc b/mojo/public/cpp/environment/lib/environment.cc
index a534a43cdb85e1016f0065c0fdc67ebee71d26f3..5fde8f791154d00249bb81d80d4ca63fce0a126f 100644
--- a/mojo/public/cpp/environment/lib/environment.cc
+++ b/mojo/public/cpp/environment/lib/environment.cc
@@ -5,7 +5,6 @@
 #include "mojo/public/cpp/environment/environment.h"
 
 #include <assert.h>
-#include <stddef.h>
 
 #include "mojo/public/c/environment/logger.h"
 #include "mojo/public/cpp/environment/lib/default_async_waiter.h"
@@ -16,8 +15,8 @@ namespace mojo {
 
 namespace {
 
-const MojoAsyncWaiter* g_default_async_waiter = NULL;
-const MojoLogger* g_default_logger = NULL;
+const MojoAsyncWaiter* g_default_async_waiter = nullptr;
+const MojoLogger* g_default_logger = nullptr;
 
 void Init(const MojoAsyncWaiter* default_async_waiter,
           const MojoLogger* default_logger) {
@@ -33,7 +32,7 @@ void Init(const MojoAsyncWaiter* default_async_waiter,
 }  // namespace
 
 Environment::Environment() {
-  Init(NULL, NULL);
+  Init(nullptr, nullptr);
 }
 
 Environment::Environment(const MojoAsyncWaiter* default_async_waiter,
@@ -46,8 +45,8 @@ Environment::~Environment() {
 
   // TODO(vtl): Maybe we should allow nesting, and restore previous default
   // async waiters and loggers?
-  g_default_async_waiter = NULL;
-  g_default_logger = NULL;
+  g_default_async_waiter = nullptr;
+  g_default_logger = nullptr;
 }
 
 // static