Replace NULL with nullptr in all C++ files.

webrtc/base/event.cc

Index: webrtc/base/event.cc
diff --git a/webrtc/base/event.cc b/webrtc/base/event.cc
index 4b348f63a1682585e419bb9518dc3aa8d4f99031..27506b3269f724c3eac4da979a7e12c652355e58 100644
--- a/webrtc/base/event.cc
+++ b/webrtc/base/event.cc
@@ -27,10 +27,9 @@ namespace rtc {
 #if defined(WEBRTC_WIN)
 
 Event::Event(bool manual_reset, bool initially_signaled) {
-  event_handle_ = ::CreateEvent(NULL,                 // Security attributes.

[tommi, 2017/02/11 09:55:34]

NULL on Windows is not exactly the same thing as nullptr.  In most cases it is,
but not always.  As an example, take a look at the return value from
timeSetEvent*.  The return type is MMRESULT, which is a number, an identifier if
successful, but NULL if not successful.

For that reason, I think we should be careful in Windows specific code with
blanket replacing NULL with nullptr. Doing so could make the code look
inconsistent with documentation and at worst, cause compilation failures.  In
the particular case we have here (CreateEvent), nullptr is fine and in my
opinion appropriate.

*
https://msdn.microsoft.com/en-us/library/windows/desktop/dd757634(v=vs.85).aspx

[Taylor Brandstetter, 2017/02/11 17:48:56]

I think that's one of the advantages of using nullptr; if you use it where you
should have used an integer type, it produces an error. I ran into this in
"audio_device_win.cc" with some APIs that take DWORD_PTRs.

For APIs that accept DWORD_PTR or ULONG_PTRs, should the style be to use "NULL",
or "reinterpret_cast<DWORD_PTR>(nullptr)"? I guess I'll bring this up in my
email to our group

-                                manual_reset,
-                                initially_signaled,
-                                NULL);                // Name.
+  event_handle_ = ::CreateEvent(nullptr,  // Security attributes.
+                                manual_reset, initially_signaled,
+                                nullptr);  // Name.
   RTC_CHECK(event_handle_);
 }
 
@@ -56,8 +55,8 @@ bool Event::Wait(int milliseconds) {
 Event::Event(bool manual_reset, bool initially_signaled)
     : is_manual_reset_(manual_reset),
       event_status_(initially_signaled) {
-  RTC_CHECK(pthread_mutex_init(&event_mutex_, NULL) == 0);
-  RTC_CHECK(pthread_cond_init(&event_cond_, NULL) == 0);
+  RTC_CHECK(pthread_mutex_init(&event_mutex_, nullptr) == 0);
+  RTC_CHECK(pthread_cond_init(&event_cond_, nullptr) == 0);
 }
 
 Event::~Event() {
@@ -93,7 +92,7 @@ bool Event::Wait(int milliseconds) {
     ts.tv_nsec = (milliseconds % 1000) * 1000000;
 #else
     struct timeval tv;
-    gettimeofday(&tv, NULL);
+    gettimeofday(&tv, nullptr);
 
     ts.tv_sec = tv.tv_sec + (milliseconds / 1000);
     ts.tv_nsec = tv.tv_usec * 1000 + (milliseconds % 1000) * 1000000;