[Sync:Sharing] Make server configuration opaque to the client.

I.e. take it as bytes instead of actual proto.

Bug: 1045883
Change-Id: Id1ebc09799d69d833c49cd5dd0f36bc2ecc2ea1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2020946
Commit-Queue: vitaliii <vitaliii@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Alex Chau <alexchau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735464}

chrome/browser/sharing/proto/sharing_message.proto

@@ -37,8 +37,10 @@ enum MessageType {
 }
 
 // Message for sending between devices in Sharing.
-// Next tag: 15
+// Next tag: 16
 message SharingMessage {
+  reserved 12;
+
   // Identifier of sender. required except for AckMessage.
   string sender_guid = 1;
 
@@ -62,9 +64,9 @@ message SharingMessage {
     // message. optional.
     FCMChannelConfiguration fcm_channel_configuration = 6;
 
-    // Server channel configuration. Ack message will be delivered through
-    // server channel. optional.
-    ServerChannelConfiguration server_channel_configuration = 12;
+    // Opaque server channel configuration. Ack message will be delivered
+    // through server channel. optional.
+    bytes server_channel_configuration = 15;
   }
 
   // The name of the device sending this message. optional.
@@ -119,16 +121,6 @@ message FCMChannelConfiguration {
   bytes sender_id_auth_secret = 6;
 }
 
-// Server channel configuration. Message will be delivered through server
-// channel.
-message ServerChannelConfiguration {
-  // Where to send the message to. required.
-  string channel_id = 1;
-
-  // Optional cookie set on the original request. optional.
-  bytes session_cookie = 2;
-}
-
 // Request for Sharing Discovery.
 message DiscoveryRequest {
   // required

components/sync/protocol/proto_visitors.h

@@ -800,13 +800,6 @@ VISIT_PROTO_FIELDS(const sync_pb::SharingMessageSpecifics& proto) {
   VISIT_BYTES(payload);
 }
 
-VISIT_PROTO_FIELDS(
-    const sync_pb::SharingMessageSpecifics::ChannelConfiguration::
-        ServerChannelConfiguration& proto) {
-  VISIT(channel_id);
-  VISIT_BYTES(session_cookie);
-}
-
 VISIT_PROTO_FIELDS(const sync_pb::SharingMessageSpecifics::
                        ChannelConfiguration::FCMChannelConfiguration& proto) {
   VISIT(token);
@@ -817,7 +810,7 @@ VISIT_PROTO_FIELDS(const sync_pb::SharingMessageSpecifics::
 VISIT_PROTO_FIELDS(
     const sync_pb::SharingMessageSpecifics::ChannelConfiguration& proto) {
   VISIT(fcm);
-  VISIT(server);
+  VISIT_BYTES(server);
 }
 
 VISIT_PROTO_FIELDS(const sync_pb::SyncCycleCompletedEventInfo& proto) {

components/sync/protocol/sharing_message_specifics.proto

@@ -21,13 +21,6 @@ message SharingMessageSpecifics {
   optional string message_id = 1;
 
   message ChannelConfiguration {
-    message ServerChannelConfiguration {
-      // Where to send the message to.
-      optional string channel_id = 1;
-      // Optional cookie set on the original request.
-      optional bytes session_cookie = 2;
-    }
-
     message FCMChannelConfiguration {
       // FCM registration token of target device.
       optional string token = 1;
@@ -44,9 +37,9 @@ message SharingMessageSpecifics {
       // FCM channel configuration. Message will be delivered as a FCM message.
       FCMChannelConfiguration fcm = 1;
 
-      // Server channel configuration. Message will be delivered through server
-      // channel.
-      ServerChannelConfiguration server = 2;
+      // Opaque server channel configuration. Message will be delivered through
+      // server channel.
+      bytes server = 2;
     }
   }