[rtcp] Nack::Parse updated not to use RTCPUtility

webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h

Index: webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h b/webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h
index b6acae5aab196a21d1876ff6df7b6118fd7f59f4..83b3ba954b6f8652ab2cd230d331b024d8672177 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h
@@ -16,21 +16,19 @@
 #include "webrtc/base/basictypes.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rtpfb.h"
-#include "webrtc/modules/rtp_rtcp/source/rtcp_utility.h"
 
 namespace webrtc {
 namespace rtcp {
+class CommonHeader;
 
 class Nack : public Rtpfb {
  public:
-  const uint8_t kFeedbackMessageType = 1;
-  Nack() {}
-
-  virtual ~Nack() {}
+  static constexpr uint8_t kFeedbackMessageType = 1;
+  Nack();
+  ~Nack() override;
 
   // Parse assumes header is already parsed and validated.
-  bool Parse(const RTCPUtility::RtcpCommonHeader& header,
-             const uint8_t* payload);  // Size of the payload is in the header.
+  bool Parse(const CommonHeader& packet);
 
   void WithList(const uint16_t* nack_list, size_t length);
   const std::vector<uint16_t>& packet_ids() const { return packet_ids_; }
@@ -44,7 +42,7 @@ class Nack : public Rtpfb {
   size_t BlockLength() const override;
 
  private:
-  const size_t kNackItemLength = 4;
+  static constexpr size_t kNackItemLength = 4;
   struct PackedNack {
     uint16_t first_pid;
     uint16_t bitmask;