Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/win32window.cc

Index: webrtc/base/win32window.cc
diff --git a/webrtc/base/win32window.cc b/webrtc/base/win32window.cc
index 9abbc86807a63835165b819f0e6689b5e5b80815..0e02eef1dc50badba3227c1e1a262bd294004d8a 100644
--- a/webrtc/base/win32window.cc
+++ b/webrtc/base/win32window.cc
@@ -19,14 +19,13 @@ namespace rtc {
 ///////////////////////////////////////////////////////////////////////////////
 
 static const wchar_t kWindowBaseClassName[] = L"WindowBaseClass";
-HINSTANCE Win32Window::instance_ = NULL;
+HINSTANCE Win32Window::instance_ = nullptr;
 ATOM Win32Window::window_class_ = 0;
 
-Win32Window::Win32Window() : wnd_(NULL) {
-}
+Win32Window::Win32Window() : wnd_(nullptr) {}
 
 Win32Window::~Win32Window() {
-  RTC_DCHECK(NULL == wnd_);
+  RTC_DCHECK(nullptr == wnd_);
 }
 
 bool Win32Window::Create(HWND parent, const wchar_t* title, DWORD style,
@@ -58,9 +57,9 @@ bool Win32Window::Create(HWND parent, const wchar_t* title, DWORD style,
       return false;
     }
   }
-  wnd_ = ::CreateWindowEx(exstyle, kWindowBaseClassName, title, style,
-                          x, y, cx, cy, parent, NULL, instance_, this);
-  return (NULL != wnd_);
+  wnd_ = ::CreateWindowEx(exstyle, kWindowBaseClassName, title, style, x, y, cx,
+                          cy, parent, nullptr, instance_, this);
+  return (nullptr != wnd_);
 }
 
 void Win32Window::Destroy() {
@@ -109,7 +108,7 @@ LRESULT Win32Window::WndProc(HWND hwnd, UINT uMsg,
     }
     if (WM_NCDESTROY == uMsg) {
       ::SetWindowLongPtr(hwnd, GWLP_USERDATA, NULL);
-      that->wnd_ = NULL;
+      that->wnd_ = nullptr;
       that->OnNcDestroy();
     }
     if (handled) {