Style fixes in rtcp_packet/

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

Index: webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h b/webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h
index a02aad642227ee2415dff800bd13e00f6274a01e..8b32366e2427d2b0657be3cb02a161be9820fada 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h
@@ -27,8 +27,8 @@ class Tmmbn : public Rtpfb {
  public:
   static constexpr uint8_t kFeedbackMessageType = 4;
 
-  Tmmbn() {}
-  ~Tmmbn() override {}
+  Tmmbn();
+  ~Tmmbn() override;
 
   // Parse assumes header is already parsed and validated.
   bool Parse(const CommonHeader& packet);
@@ -37,18 +37,14 @@ class Tmmbn : public Rtpfb {
 
   const std::vector<TmmbItem>& items() const { return items_; }
 
- protected:
+  size_t BlockLength() const override;
+
   bool Create(uint8_t* packet,
               size_t* index,
               size_t max_length,
               RtcpPacket::PacketReadyCallback* callback) const override;
 
  private:
-  size_t BlockLength() const override {
-    return kHeaderLength + kCommonFeedbackLength +
-           TmmbItem::kLength * items_.size();
-  }
-
   // Media ssrc is unused, shadow base class setter and getter.
   void SetMediaSsrc(uint32_t ssrc);
   uint32_t media_ssrc() const;