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

sync/internal_api/public/sessions/model_neutral_state.h

Index: sync/internal_api/public/sessions/model_neutral_state.h
diff --git a/sync/internal_api/public/sessions/model_neutral_state.h b/sync/internal_api/public/sessions/model_neutral_state.h
index a9c1c440bb0b0b1627c03811d19f0133eec36872..147de50ffcaea1ed75bd47eb1f188bcc89c9ac76 100644
--- a/sync/internal_api/public/sessions/model_neutral_state.h
+++ b/sync/internal_api/public/sessions/model_neutral_state.h
@@ -48,7 +48,9 @@ struct ModelNeutralState {
   // Any protocol errors that we received during this sync session.
   SyncProtocolError sync_protocol_error;
 
-  // Records the most recent results of PostCommit and GetUpdates commands.
+  // Records the most recent results of GetKey, PostCommit and GetUpdates
+  // commands.
+  SyncerError last_get_key_result;

[tim (not reviewing), 2012/07/26 21:53:15]

We don't technically have GetKey in this patch anymore, consider moving this
aside.

[Nicolas Zea, 2012/07/27 00:43:15]

For the sake of making it clear where the failure is coming from (since you
could successfully download updates while failing to get a keystore key), I
think it's worth tracking on its own. 

   SyncerError last_download_updates_result;
   SyncerError commit_result;