[Sync] Add support for server controlled nudge delays

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 fe2a875bccc799ccfdf682b30014df1c3b9dcba6..b03aa90c0210f479602aab9e90b321337b50fa42 100644
--- a/sync/engine/syncer_proto_util.cc
+++ b/sync/engine/syncer_proto_util.cc
@@ -420,9 +420,9 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
     }
 
     if (command.has_sessions_commit_delay_seconds()) {
-      session->delegate()->OnReceivedSessionsCommitDelay(
-          base::TimeDelta::FromSeconds(
-              command.sessions_commit_delay_seconds()));
+      std::map<ModelType, int> delay_map;
+      delay_map[SESSIONS] = command.sessions_commit_delay_seconds() * 1000;
+      session->delegate()->OnReceivedCustomNudgeDelays(delay_map);
     }
 
     if (command.has_client_invalidation_hint_buffer_size()) {
@@ -434,6 +434,19 @@ SyncerError SyncerProtoUtil::PostClientToServerMessage(
       session->delegate()->OnReceivedGuRetryDelay(
           base::TimeDelta::FromSeconds(command.gu_retry_delay_seconds()));
     }
+
+    if (command.custom_nudge_delays_size() > 0) {
+      // Note that because this happens after the sessions_commit_delay_seconds
+      // handling, any SESSIONS value in this map will override the one in
+      // sessions_commit_delay_seconds.
+      std::map<ModelType, int> delay_map;
+      for (int i = 0; i < command.custom_nudge_delays_size(); ++i) {
+        delay_map[GetModelTypeFromSpecificsFieldNumber(

[rlarocque, 2014/08/20 00:13:31]

Should we be more defensive against unknown model types here?

[Nicolas Zea, 2014/08/20 22:49:43]

Good call, this has bitten us before.

+            command.custom_nudge_delays(i).datatype_id())] =
+            command.custom_nudge_delays(i).delay_ms();
+      }
+      session->delegate()->OnReceivedCustomNudgeDelays(delay_map);
+    }
   }
 
   // Now do any special handling for the error type and decide on the return