rtcp::Nack packet moved into own file and got Parse function

webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.cc

Index: webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.cc b/webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.cc
similarity index 88%
copy from webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.cc
copy to webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.cc
index d1ee401dab921e4f7bdd7a5d90a7a0a85b624b38..b5571d45a36d83636d748276b92fc963f5ff7707 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.cc
@@ -8,14 +8,14 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/psfb.h"
+#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.h"
 
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 
 namespace webrtc {
 namespace rtcp {
 
-// RFC 4585: Feedback format.
+// RFC 4585, Section 6.1: Feedback format.
 //
 // Common packet format:
 //
@@ -31,12 +31,12 @@ namespace rtcp {
 //   :            Feedback Control Information (FCI)                 :
 //   :                                                               :
 
-void Psfb::ParseCommonFeedback(const uint8_t* payload) {
+void Rtpfb::ParseCommonFeedback(const uint8_t* payload) {
   sender_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[0]);
   media_ssrc_ = ByteReader<uint32_t>::ReadBigEndian(&payload[4]);
 }
 
-void Psfb::CreateCommonFeedback(uint8_t* payload) const {
+void Rtpfb::CreateCommonFeedback(uint8_t* payload) const {
   ByteWriter<uint32_t>::WriteBigEndian(&payload[0], sender_ssrc_);
   ByteWriter<uint32_t>::WriteBigEndian(&payload[4], media_ssrc_);
 }