Deprecate FLAGS_quic_postpone_multipath_flag_validation.

net/quic/core/quic_connection.cc

Index: net/quic/core/quic_connection.cc
diff --git a/net/quic/core/quic_connection.cc b/net/quic/core/quic_connection.cc
index a3765d60248cf3033a8428eaa50f3f30b8ef547a..f8d0049da3523e1c85741909abb710e34b7b714a 100644
--- a/net/quic/core/quic_connection.cc
+++ b/net/quic/core/quic_connection.cc
@@ -593,18 +593,6 @@ bool QuicConnection::OnUnauthenticatedHeader(const QuicPacketHeader& header) {
   // here.
   DCHECK_EQ(connection_id_, header.public_header.connection_id);
 
-  if (!FLAGS_quic_postpone_multipath_flag_validation) {
-    // Multipath is not enabled, but a packet with multipath flag on is
-    // received.
-    if (!multipath_enabled_ && header.public_header.multipath_flag) {
-      const string error_details =
-          "Received a packet with multipath flag but multipath is not enabled.";
-      QUIC_BUG << error_details;
-      CloseConnection(QUIC_BAD_MULTIPATH_FLAG, error_details,
-                      ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
-      return false;
-    }
-  }
   if (!packet_generator_.IsPendingPacketEmpty()) {
     // Incoming packets may change a queued ACK frame.
     const string error_details =
@@ -1430,17 +1418,15 @@ bool QuicConnection::ProcessValidatedPacket(const QuicPacketHeader& header) {
     return false;
   }
 
-  if (FLAGS_quic_postpone_multipath_flag_validation) {
-    // Multipath is not enabled, but a packet with multipath flag on is
-    // received.
-    if (!multipath_enabled_ && header.public_header.multipath_flag) {
-      const string error_details =
-          "Received a packet with multipath flag but multipath is not enabled.";
-      QUIC_BUG << error_details;
-      CloseConnection(QUIC_BAD_MULTIPATH_FLAG, error_details,
-                      ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
-      return false;
-    }
+  // Multipath is not enabled, but a packet with multipath flag on is
+  // received.
+  if (!multipath_enabled_ && header.public_header.multipath_flag) {
+    const string error_details =
+        "Received a packet with multipath flag but multipath is not enabled.";
+    QUIC_BUG << error_details;
+    CloseConnection(QUIC_BAD_MULTIPATH_FLAG, error_details,
+                    ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET);
+    return false;
   }
 
   if (version_negotiation_state_ != NEGOTIATED_VERSION) {