replace NULL->nullptr in src/remoting.

remoting/host/linux/x_server_clipboard_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "remoting/base/constants.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // X11 headers must be #included after gtest.h, since the X11 headers define
 // some macros that cause errors in gtest-type-util.h.
 #include <X11/Xlib.h>
 #include "remoting/host/linux/x_server_clipboard.h"
 
 namespace remoting {
 
 namespace {
 
 class ClipboardTestClient {
  public:
-  ClipboardTestClient() : display_(NULL) {}
+  ClipboardTestClient() : display_(nullptr) {}
   ~ClipboardTestClient() {}
 
   void Init(Display* display) {
     display_ = display;
     clipboard_.Init(display,
                     base::Bind(&ClipboardTestClient::OnClipboardChanged,
                                base::Unretained(this)));
   }
 
   void SetClipboardData(const std::string& clipboard_data) {
@@ skipping 30 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ClipboardTestClient);
 };
 
 }  // namespace
 
 class XServerClipboardTest : public testing::Test {
  public:
   void SetUp() override {
     // XSynchronize() ensures that PumpXEvents() fully processes all X server
     // requests and responses before returning to the caller.
-    Display* display1 = XOpenDisplay(NULL);
+    Display* display1 = XOpenDisplay(nullptr);
     XSynchronize(display1, True);
     client1_.Init(display1);
-    Display* display2 = XOpenDisplay(NULL);
+    Display* display2 = XOpenDisplay(nullptr);
     XSynchronize(display2, True);
     client2_.Init(display2);
   }
 
   void TearDown() override {
     XCloseDisplay(client1_.display());
     XCloseDisplay(client2_.display());
   }
 
   void PumpXEvents() {
@@ skipping 24 matching lines @@
   client2_.SetClipboardData("Text3");
   PumpXEvents();
   EXPECT_EQ("Text3", client1_.clipboard_data());
 
   client2_.SetClipboardData("Text4");
   PumpXEvents();
   EXPECT_EQ("Text4", client1_.clipboard_data());
 }
 
 }  // namespace remoting