Implement PRIORITY_UPDATE frame in HTTP/2 decoder.

Protected by FLAGS_gfe2_restart_flag_http2_parse_priority_update_frame.

PiperOrigin-RevId: 350771697
Change-Id: Ia630bd2d2a2211c8f6238676f6024dcf7ada924d
diff --git a/http2/decoder/decode_http2_structures.h b/http2/decoder/decode_http2_structures.h
index 4cb93a3..9b26d33 100644
--- a/http2/decoder/decode_http2_structures.h
+++ b/http2/decoder/decode_http2_structures.h
@@ -28,6 +28,8 @@
 QUICHE_EXPORT_PRIVATE void DoDecode(Http2WindowUpdateFields* out,
                                     DecodeBuffer* b);
 QUICHE_EXPORT_PRIVATE void DoDecode(Http2AltSvcFields* out, DecodeBuffer* b);
+QUICHE_EXPORT_PRIVATE void DoDecode(Http2PriorityUpdateFields* out,
+                                    DecodeBuffer* b);
 
 }  // namespace http2