Replace NULL with nullptr in all C++ files.

webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc b/webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc
index 2d847c17a608ba5f64dae5f938b3ca4b7689693f..e461e8143c8bac6bd1e3690c84fdf23110278a40 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_format_video_generic.cc
@@ -21,11 +21,10 @@ static const size_t kGenericHeaderLength = 1;
 
 RtpPacketizerGeneric::RtpPacketizerGeneric(FrameType frame_type,
                                            size_t max_payload_len)
-    : payload_data_(NULL),
+    : payload_data_(nullptr),
       payload_size_(0),
       max_payload_len_(max_payload_len - kGenericHeaderLength),
-      frame_type_(frame_type) {
-}
+      frame_type_(frame_type) {}
 
 RtpPacketizerGeneric::~RtpPacketizerGeneric() {
 }
@@ -92,7 +91,7 @@ std::string RtpPacketizerGeneric::ToString() {
 bool RtpDepacketizerGeneric::Parse(ParsedPayload* parsed_payload,
                                    const uint8_t* payload_data,
                                    size_t payload_data_length) {
-  assert(parsed_payload != NULL);
+  assert(parsed_payload != nullptr);
   if (payload_data_length == 0) {
     LOG(LS_ERROR) << "Empty payload.";
     return false;