Replace NULL with nullptr in webrtc/video.

webrtc/video/send_statistics_proxy.cc

Index: webrtc/video/send_statistics_proxy.cc
diff --git a/webrtc/video/send_statistics_proxy.cc b/webrtc/video/send_statistics_proxy.cc
index 3d82a3b0468d121bf8fe6b2416851b2239e91a81..f4c0e608a865bc872387df4dae2c9838dcb1c8d3 100644
--- a/webrtc/video/send_statistics_proxy.cc
+++ b/webrtc/video/send_statistics_proxy.cc
@@ -407,8 +407,7 @@ void SendStatisticsProxy::OnSetRates(uint32_t bitrate_bps, int framerate) {
 void SendStatisticsProxy::OnSendEncodedImage(
     const EncodedImage& encoded_image,
     const RTPVideoHeader* rtp_video_header) {
-  size_t simulcast_idx =
-      rtp_video_header != nullptr ? rtp_video_header->simulcastIdx : 0;
+  size_t simulcast_idx = rtp_video_header ? rtp_video_header->simulcastIdx : 0;
   if (simulcast_idx >= config_.rtp.ssrcs.size()) {
     LOG(LS_ERROR) << "Encoded image outside simulcast range (" << simulcast_idx
                   << " >= " << config_.rtp.ssrcs.size() << ").";
@@ -450,7 +449,7 @@ void SendStatisticsProxy::OnSendEncodedImage(
     }
   }
 
-  if (encoded_image.qp_ != -1 && rtp_video_header != nullptr &&
+  if (encoded_image.qp_ != -1 && rtp_video_header &&
       rtp_video_header->codec == kRtpVideoVp8) {
     int spatial_idx =
         (config_.rtp.ssrcs.size() == 1) ? -1 : static_cast<int>(simulcast_idx);
@@ -517,8 +516,8 @@ void SendStatisticsProxy::DataCountersUpdated(
     uint32_t ssrc) {
   rtc::CritScope lock(&crit_);
   VideoSendStream::StreamStats* stats = GetStatsEntry(ssrc);
-  RTC_DCHECK(stats != nullptr)
-      << "DataCountersUpdated reported for unknown ssrc: " << ssrc;
+  RTC_DCHECK(stats) << "DataCountersUpdated reported for unknown ssrc: "
+                    << ssrc;
 
   stats->rtp_stats = counters;
   if (uma_container_->first_rtp_stats_time_ms_ == -1)