Client-side changes to support retry GU.

sync/engine/syncer_proto_util.cc

Index: sync/engine/syncer_proto_util.cc
diff --git a/sync/engine/syncer_proto_util.cc b/sync/engine/syncer_proto_util.cc
index bfd8151bef03405bd0b8913391b0ab53ef16d5ac..bcc0bd47b1a4aad7ed301dfd58c2b5d8ba3714da 100644
--- a/sync/engine/syncer_proto_util.cc
+++ b/sync/engine/syncer_proto_util.cc
@@ -433,6 +433,11 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
       session->delegate()->OnReceivedClientInvalidationHintBufferSize(
           command.client_invalidation_hint_buffer_size());
     }
+
+    if (command.has_gu_retry_delay_seconds()) {
+      session->delegate()->OnReceivedGuRetryDelay(
+          base::TimeDelta::FromSeconds(command.gu_retry_delay_seconds()));
+    }
   }
 
   // Now do any special handling for the error type and decide on the return