[Sync] Add support for performing a GetKey on startup.

sync/protocol/sync.proto

Index: sync/protocol/sync.proto
diff --git a/sync/protocol/sync.proto b/sync/protocol/sync.proto
index ec9a1d2365cdc4991977fe3a17d85ea2f9606d8e..d1af6d7261c7626820ca574b14a5f1c422672a09 100644
--- a/sync/protocol/sync.proto
+++ b/sync/protocol/sync.proto
@@ -455,6 +455,13 @@ message AuthenticateMessage {
   required string auth_token = 1;
 };
 
+message GetEncryptionKeyMessage {

[tim (not reviewing), 2012/07/19 21:42:03]

Comments on the messages + fields.

[Nicolas Zea, 2012/07/24 22:51:24]

Done.

+}
+
+message GetEncryptionKeyResponse {
+  optional bytes key = 1;
+}
+
 message ClientToServerMessage {
   required string share = 1;
   optional int32 protocol_version = 2 [default = 31];
@@ -463,6 +470,7 @@ message ClientToServerMessage {
     GET_UPDATES = 2;
     AUTHENTICATE = 3;
     CLEAR_DATA = 4;
+    GET_ENCRYPTION_KEY = 5;
   }
 
   required Contents message_contents = 3;
@@ -483,6 +491,8 @@ message ClientToServerMessage {
   // This is only sent on the first getupdates of every sync cycle,
   // as an optimization to save bandwidth.
   optional DebugInfo debug_info = 10;
+
+  optional GetEncryptionKeyMessage get_encryption_key = 11;
 };
 
 message CommitResponse {
@@ -625,25 +635,6 @@ message ClientToServerResponse {
   optional CommitResponse commit = 1;
   optional GetUpdatesResponse get_updates = 2;
   optional AuthenticateResponse authenticate = 3;
-  // DEPRECATED - this field was never used in production.
-  // optional ClearUserDataResponse clear_user_data = 9;
-  optional GetUpdatesMetadataResponse stream_metadata = 10;
-  // If GetUpdatesStreamingResponse is contained in the ClientToServerResponse,
-  // none of the other fields (error_code and etc) will be set.
-  optional GetUpdatesStreamingResponse stream_data = 11;
-
-  message Error {
-    optional SyncEnums.ErrorType error_type = 1 [default = UNKNOWN];
-    optional string error_description       = 2;
-    optional string url                     = 3;
-    optional SyncEnums.Action action        = 4 [default = UNKNOWN_ACTION];
-
-    // Currently only meaningful if |error_type| is throttled. If this field
-    // is absent then the whole client (all datatypes) is throttled.
-    repeated int32 error_data_type_ids = 5;
-  }
-
-  optional Error error = 13;
 
   // Up until protocol_version 24, the default was SUCCESS which made it
   // impossible to add new enum values since older clients would parse any
@@ -663,9 +654,29 @@ message ClientToServerResponse {
 
   optional ClientCommand client_command = 7;
   optional ProfilingData profiling_data = 8;
+  // DEPRECATED - this field was never used in production.
+  // optional ClearUserDataResponse clear_user_data = 9;
+  optional GetUpdatesMetadataResponse stream_metadata = 10;
+  // If GetUpdatesStreamingResponse is contained in the ClientToServerResponse,
+  // none of the other fields (error_code and etc) will be set.
+  optional GetUpdatesStreamingResponse stream_data = 11;
 
   // The data types whose storage has been migrated.  Present when the value of
   // error_code is MIGRATION_DONE.
   repeated int32 migrated_data_type_id = 12;
+
+  message Error {
+    optional SyncEnums.ErrorType error_type = 1 [default = UNKNOWN];
+    optional string error_description       = 2;
+    optional string url                     = 3;
+    optional SyncEnums.Action action        = 4 [default = UNKNOWN_ACTION];
+
+    // Currently only meaningful if |error_type| is throttled. If this field
+    // is absent then the whole client (all datatypes) is throttled.
+    repeated int32 error_data_type_ids = 5;
+  }
+  optional Error error = 13;
+
+  optional GetEncryptionKeyResponse get_encryption_key = 14;
 };