Replace NULL with nullptr in all C++ files.

webrtc/base/win32window_unittest.cc

Index: webrtc/base/win32window_unittest.cc
diff --git a/webrtc/base/win32window_unittest.cc b/webrtc/base/win32window_unittest.cc
index 3738a7f4a50fb8cd1ab5c6be9e6a1de7fd01481c..f814752e39f744bf07b250bf7703c3af3aff8d9c 100644
--- a/webrtc/base/win32window_unittest.cc
+++ b/webrtc/base/win32window_unittest.cc
@@ -39,16 +39,16 @@ class TestWindow : public rtc::Win32Window {
 
 TEST(Win32WindowTest, Basics) {
   TestWindow wnd;
-  EXPECT_TRUE(wnd.handle() == NULL);
+  EXPECT_TRUE(wnd.handle() == nullptr);
   EXPECT_FALSE(wnd.destroyed());
   EXPECT_TRUE(wnd.Create(0, L"Test", 0, 0, 0, 0, 100, 100));
-  EXPECT_TRUE(wnd.handle() != NULL);
+  EXPECT_TRUE(wnd.handle() != nullptr);
   EXPECT_EQ(kDummyResult, ::SendMessage(wnd.handle(), WM_USER, 1, 2));
   EXPECT_EQ(static_cast<UINT>(WM_USER), wnd.msg().message);
   EXPECT_EQ(1u, wnd.msg().wParam);
   EXPECT_EQ(2l, wnd.msg().lParam);
   wnd.Destroy();
-  EXPECT_TRUE(wnd.handle() == NULL);
+  EXPECT_TRUE(wnd.handle() == nullptr);
   EXPECT_TRUE(wnd.destroyed());
 }
 
@@ -56,10 +56,10 @@ TEST(Win32WindowTest, MultipleWindows) {
   TestWindow wnd1, wnd2;
   EXPECT_TRUE(wnd1.Create(0, L"Test", 0, 0, 0, 0, 100, 100));
   EXPECT_TRUE(wnd2.Create(0, L"Test", 0, 0, 0, 0, 100, 100));
-  EXPECT_TRUE(wnd1.handle() != NULL);
-  EXPECT_TRUE(wnd2.handle() != NULL);
+  EXPECT_TRUE(wnd1.handle() != nullptr);
+  EXPECT_TRUE(wnd2.handle() != nullptr);
   wnd1.Destroy();
   wnd2.Destroy();
-  EXPECT_TRUE(wnd2.handle() == NULL);
-  EXPECT_TRUE(wnd1.handle() == NULL);
+  EXPECT_TRUE(wnd2.handle() == nullptr);
+  EXPECT_TRUE(wnd1.handle() == nullptr);
 }