replace NULL->nullptr in src/remoting.

remoting/host/chromoting_host_unittest.cc

Index: remoting/host/chromoting_host_unittest.cc
diff --git a/remoting/host/chromoting_host_unittest.cc b/remoting/host/chromoting_host_unittest.cc
index 84b4f7deee45e225cb95d21ba0c42051de08ec2a..19efc25c37052923a67f09d65b70870f9c6d9550 100644
--- a/remoting/host/chromoting_host_unittest.cc
+++ b/remoting/host/chromoting_host_unittest.cc
@@ -196,7 +196,7 @@ class ChromotingHostTest : public testing::Test {
         connection.Pass(),
         desktop_environment_factory_.get(),
         base::TimeDelta(),
-        NULL,
+        nullptr,
         std::vector<HostExtension*>()));
 
     connection_ptr->set_host_stub(client.get());
@@ -227,7 +227,7 @@ class ChromotingHostTest : public testing::Test {
 
   void TearDown() override {
     // Make sure that the host has been properly deleted.
-    DCHECK(host_.get() == NULL);
+    DCHECK(host_.get() == nullptr);
   }
 
   // Change the session route for |client1_|.
@@ -322,7 +322,7 @@ class ChromotingHostTest : public testing::Test {
 
   void StopAndReleaseTaskRunner() {
     host_.reset();
-    task_runner_ = NULL;
+    task_runner_ = nullptr;
     desktop_environment_factory_.reset();
   }