common: added a field in HCM proto to be able to reverse the order of HTTP encoder filters. (#4721)

Added a field in HCM proto to be able to reverse the order of HTTP encoder filters. The field is set false by default, indicating HTTP encoder filters have the same order as configured in the filter
chain. If true, their order will be reversed.

Risk Level: low
Testing: bazel test //test/...
Part of #4599

Signed-off-by: Qi (Anna) Wang <qiwang@qiwang-macbookpro.roam.corp.google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 0ccc70ae77909baadcb07dd0c9ca2ef583dde3b5

envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto

@@ -19,7 +19,7 @@ import "gogoproto/gogo.proto";
 // [#protodoc-title: HTTP connection manager]
 // HTTP connection manager :ref:`configuration overview <config_http_conn_man>`.
 
-// [#comment:next free field: 27]
+// [#comment:next free field: 28]
 message HttpConnectionManager {
   enum CodecType {
     option (gogoproto.goproto_enum_prefix) = false;
@@ -348,6 +348,15 @@ message HttpConnectionManager {
     repeated HttpFilter filters = 2;
   };
   repeated UpgradeConfig upgrade_configs = 23;
+
+  // If true, the order of encoder filters will be reversed to that of filters
+  // configured in the HTTP filter chain. Otherwise, it will keep the existing
+  // order.
+  // Note: this is a bug fix for Envoy, which is designed to have the reversed
+  // order of encode filters to that of decode ones, (see
+  // https://github.com/envoyproxy/envoy/issues/4599 for details). When we remove this field, envoy
+  // will have the same behavior when it sets true.
+  google.protobuf.BoolValue bugfix_reverse_encode_order = 27 [deprecated = true];
 }
 
 message Rds {