Implement FrameMarking header extension support

webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h

Index: webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h b/webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h
index dc63140271f92812a5a69fdcc3d9f79a7436568f..020f05183480febe235e6b9e70bbe9acbb7d1628 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h
@@ -182,5 +182,20 @@ class RtpMid : public BaseRtpStringExtension {
   static constexpr const char kUri[] = "urn:ietf:params:rtp-hdrext:sdes:mid";
 };
 
+class FrameMarking {
+ public:
+  static constexpr RTPExtensionType kId = kRtpExtensionFrameMarking;
+  static constexpr const char* kUri = "urn:ietf:params:rtp-hdrext:framemarking";
+  static bool Parse(rtc::ArrayView<const uint8_t> data,
+                    FrameMarks* frame_marks);
+  static size_t ValueSize(const FrameMarks& frame_marks);
+  static bool Write(uint8_t* data, const FrameMarks& frame_marks);
+
+  static uint8_t CreateLayerId(const RTPVideoHeaderVP9& vp9);
+
+ private:
+  static bool IsScalable(const FrameMarks& frame_marks);
+};
+
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_RTP_HEADER_EXTENSIONS_H_