Replace NULL with nullptr in all C++ files.

webrtc/modules/video_capture/video_capture_impl.cc

Index: webrtc/modules/video_capture/video_capture_impl.cc
diff --git a/webrtc/modules/video_capture/video_capture_impl.cc b/webrtc/modules/video_capture/video_capture_impl.cc
index fe0906e639c4da66b7898d4d6c7147ab658dd6eb..9892bdda3a3e2c5350f5146c4bc639e7768cebaf 100644
--- a/webrtc/modules/video_capture/video_capture_impl.cc
+++ b/webrtc/modules/video_capture/video_capture_impl.cc
@@ -80,22 +80,22 @@ int32_t VideoCaptureImpl::RotationInDegrees(VideoRotation rotation,
 }
 
 VideoCaptureImpl::VideoCaptureImpl()
-    : _deviceUniqueId(NULL),
+    : _deviceUniqueId(nullptr),
       _apiCs(*CriticalSectionWrapper::CreateCriticalSection()),
       _captureDelay(0),
       _requestedCapability(),
       _lastProcessTimeNanos(rtc::TimeNanos()),
       _lastFrameRateCallbackTimeNanos(rtc::TimeNanos()),
-      _dataCallBack(NULL),
+      _dataCallBack(nullptr),
       _lastProcessFrameTimeNanos(rtc::TimeNanos()),
       _rotateFrame(kVideoRotation_0),
       apply_rotation_(false) {
-    _requestedCapability.width = kDefaultWidth;
-    _requestedCapability.height = kDefaultHeight;
-    _requestedCapability.maxFPS = 30;
-    _requestedCapability.rawType = kVideoI420;
-    _requestedCapability.codecType = kVideoCodecUnknown;
-    memset(_incomingFrameTimesNanos, 0, sizeof(_incomingFrameTimesNanos));
+  _requestedCapability.width = kDefaultWidth;
+  _requestedCapability.height = kDefaultHeight;
+  _requestedCapability.maxFPS = 30;
+  _requestedCapability.rawType = kVideoI420;
+  _requestedCapability.codecType = kVideoCodecUnknown;
+  memset(_incomingFrameTimesNanos, 0, sizeof(_incomingFrameTimesNanos));
 }
 
 VideoCaptureImpl::~VideoCaptureImpl()
@@ -115,7 +115,7 @@ void VideoCaptureImpl::RegisterCaptureDataCallback(
 
 void VideoCaptureImpl::DeRegisterCaptureDataCallback() {
     CriticalSectionScoped cs(&_apiCs);
-    _dataCallBack = NULL;
+    _dataCallBack = nullptr;
 }
 int32_t VideoCaptureImpl::DeliverCapturedFrame(VideoFrame& captureFrame) {
   UpdateFrameCount();  // frame count used for local frame rate callback.