Sync protocol cleanup: Remove AUTHENTICATE message

This was another type of protocol message next to GET_UPDATES and
COMMIT, which hadn't been used in a long time. This CL removes the
corresponding protos.

Bug: 960755
Change-Id: Iabfafd349f1eac4acc453fe8f668667028ce2341
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1820799Reviewed-by: Jan Krcal <jkrcal@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699296}

components/sync/protocol/sync.proto

@@ -700,15 +700,7 @@ message GetUpdatesMessage {
   reserved "requested_types";
 };
 
-message AuthenticateMessage {
-  required string auth_token = 1;
-};
-
 // Message from a client asking the server to clear its data.
-//
-// A client makes a ClearServerData request when it transitions to passphrase
-// encryption to ensure the server deletes any plaintext data that may have been
-// synced previously.
 message ClearServerDataMessage {
   // No arguments needed as the store birthday and user identifier are part of
   // an enclosing message.
@@ -775,7 +767,7 @@ message ClientToServerMessage {
   enum Contents {
     COMMIT = 1;
     GET_UPDATES = 2;
-    AUTHENTICATE = 3;
+    DEPRECATED_3 = 3;
     DEPRECATED_4 = 4;
     CLEAR_SERVER_DATA = 5;
   }
@@ -787,7 +779,8 @@ message ClientToServerMessage {
   required Contents message_contents = 3;
   optional CommitMessage commit = 4;
   optional GetUpdatesMessage get_updates = 5;
-  optional AuthenticateMessage authenticate = 6;
+  reserved 6;
+  reserved "authenticate";
 
   optional DeprecatedMessage deprecated_field_9 = 9 [deprecated = true];
 
@@ -965,25 +958,11 @@ message GetUpdatesStreamingResponse {
   repeated SyncEntity entries = 1;
 };
 
-// A user-identifying struct.  For a given Google account the email and display
-// name can change, but obfuscated_id should be constant.
-// The obfuscated id is optional because at least one planned use of the proto
-// (sharing) does not require it.
-message UserIdentification {
-  required string email = 1;          // the user's full primary email address.
-  optional string display_name = 2;   // the user's display name.
-  optional string obfuscated_id = 3;  // an obfuscated, opaque user id.
-};
-
-message AuthenticateResponse {
-  // Optional only for backward compatibility.
-  optional UserIdentification user = 1;
-};
-
 message ClientToServerResponse {
   optional CommitResponse commit = 1;
   optional GetUpdatesResponse get_updates = 2;
-  optional AuthenticateResponse authenticate = 3;
+  reserved 3;
+  reserved "authenticate";
 
   // Up until protocol_version 24, the default was SUCCESS which made it
   // impossible to add new enum values since older clients would parse any

components/sync/test/engine/mock_connection_manager.cc

@@ -146,7 +146,6 @@ bool MockConnectionManager::PostBufferToPath(PostBufferParams* params,
   }
   bool result = true;
   EXPECT_TRUE(!store_birthday_sent_ || post.has_store_birthday() ||
-              post.message_contents() == ClientToServerMessage::AUTHENTICATE ||
               post.message_contents() ==
                   ClientToServerMessage::CLEAR_SERVER_DATA);
   store_birthday_sent_ = true;

components/sync/test/engine/mock_connection_manager.h

@@ -371,11 +371,6 @@ class MockConnectionManager : public ServerConnectionManager {
   // The keystore key we return for a GetUpdates with need_encryption_key set.
   std::string keystore_key_;
 
-  // The AUTHENTICATE response we'll return for auth requests.
-  sync_pb::AuthenticateResponse auth_response_;
-  // What we use to determine if we should return SUCCESS or BAD_AUTH_TOKEN.
-  std::string valid_access_token_;
-
   // Whether we are faking a server mandating clients to throttle requests.
   // Protected by |response_code_override_lock_|.
   bool throttling_;