replace NULL->nullptr in src/remoting.

remoting/client/jni/chromoting_jni_runtime.cc

Index: remoting/client/jni/chromoting_jni_runtime.cc
diff --git a/remoting/client/jni/chromoting_jni_runtime.cc b/remoting/client/jni/chromoting_jni_runtime.cc
index 38834dd06d033b5bc728ac02e30e1bbaf5a9c2c2..f07794801f4debabf774a7b84f8cf67d532cb73b 100644
--- a/remoting/client/jni/chromoting_jni_runtime.cc
+++ b/remoting/client/jni/chromoting_jni_runtime.cc
@@ -46,7 +46,7 @@ static void LoadNative(JNIEnv* env, jclass clazz, jobject context) {
   // runtime API keys have been specified by the environment. Unfortunately, we
   // neither launch Chromium nor have a command line, so we need to prevent
   // them from DCHECKing out when they go looking.
-  base::CommandLine::Init(0, NULL);
+  base::CommandLine::Init(0, nullptr);
 
   // Create the singleton now so that the Chromoting threads will be set up.
   remoting::ChromotingJniRuntime::GetInstance();
@@ -245,7 +245,7 @@ void ChromotingJniRuntime::DisconnectFromHost() {
   DCHECK(ui_task_runner_->BelongsToCurrentThread());
   if (session_.get()) {
     session_->Disconnect();
-    session_ = NULL;
+    session_ = nullptr;
   }
 }