Use the largest received packet instead of the most recently received packet to calculate the seque…

net/quic/core/quic_framer.h

Index: net/quic/core/quic_framer.h
diff --git a/net/quic/core/quic_framer.h b/net/quic/core/quic_framer.h
index 899202d3f0db99120d4eef454be48714aeafcd6d..55d32262fa7216a877b7b7530f845569515ad9a8 100644
--- a/net/quic/core/quic_framer.h
+++ b/net/quic/core/quic_framer.h
@@ -441,7 +441,7 @@ class NET_EXPORT_PRIVATE QuicFramer {
   bool ProcessPathId(QuicDataReader* reader, QuicPathId* path_id);
   bool ProcessPacketSequenceNumber(QuicDataReader* reader,
                                    QuicPacketNumberLength packet_number_length,
-                                   QuicPacketNumber last_packet_number,
+                                   QuicPacketNumber base_packet_number,
                                    QuicPacketNumber* packet_number);
   bool ProcessFrameData(QuicDataReader* reader, const QuicPacketHeader& header);
   bool ProcessStreamFrame(QuicDataReader* reader,
@@ -474,9 +474,10 @@ class NET_EXPORT_PRIVATE QuicFramer {
                       size_t* decrypted_length);
 
   // Checks if |path_id| is a viable path to receive packets on. Returns true
-  // and sets |last_packet_number| if the path is not closed. Returns false
+  // and sets |base_packet_number| to the packet number to calculate the
+  // incoming packet number from if the path is not closed. Returns false
   // otherwise.
-  bool IsValidPath(QuicPathId path_id, QuicPacketNumber* last_packet_number);
+  bool IsValidPath(QuicPathId path_id, QuicPacketNumber* base_packet_number);
 
   // Sets last_packet_number_. This can only be called after the packet is
   // successfully decrypted.
@@ -486,7 +487,7 @@ class NET_EXPORT_PRIVATE QuicFramer {
   // wire format version and the last seen packet number.
   QuicPacketNumber CalculatePacketNumberFromWire(
       QuicPacketNumberLength packet_number_length,
-      QuicPacketNumber last_packet_number,
+      QuicPacketNumber base_packet_number,
       QuicPacketNumber packet_number) const;
 
   // Returns the QuicTime::Delta corresponding to the time from when the framer
@@ -569,9 +570,16 @@ class NET_EXPORT_PRIVATE QuicFramer {
   std::unordered_set<QuicPathId> closed_paths_;
   // Map mapping path id to packet number of last successfully decrypted
   // received packet.
+  // TODO(ianswett): Remove when
+  // gfe2_reloadable_flag_quic_packet_numbers_largest_received is deprecated.
   std::unordered_map<QuicPathId, QuicPacketNumber> last_packet_numbers_;
   // Updated by ProcessPacketHeader when it succeeds.
   QuicPacketNumber last_packet_number_;
+  // Map mapping path id to packet number of largest successfully decrypted
+  // received packet.
+  std::unordered_map<QuicPathId, QuicPacketNumber> largest_packet_numbers_;
+  // Updated by ProcessPacketHeader when it succeeds decrypting a larger packet.
+  QuicPacketNumber largest_packet_number_;
   // The path on which last successfully decrypted packet was received.
   QuicPathId last_path_id_;
   // Updated by WritePacketHeader.