[Sync] Don't start up sync when FirstSetupCompleted is false and no setup in progress

components/sync_driver/startup_controller.h

Index: components/sync_driver/startup_controller.h
diff --git a/components/sync_driver/startup_controller.h b/components/sync_driver/startup_controller.h
index 9ebb9d56834f7a9e6d3cebfbe2bae50cfc7f03ad..bfa1b77b611116f508d4a4f8e9b038e7dc46f01b 100644
--- a/components/sync_driver/startup_controller.h
+++ b/components/sync_driver/startup_controller.h
@@ -29,7 +29,9 @@ class StartupController {
   // Starts up sync if it is requested by the user and preconditions are met.
   // Returns true if these preconditions are met, although does not imply
   // the backend was started.
-  bool TryStart();
+  // |request_immediate| will force immediate startup if true, rather than
+  // deferred, once preconditions are met.
+  bool TryStart(bool request_immediate);

[maxbogue, 2016/07/15 21:44:48]

I think the code will be much more readable if you add a second method like
TryStartImmediately() instead of a boolean parameter. It would just set
received_start_request_ and then call TryStart().

[Nicolas Zea, 2016/07/15 22:42:22]

Good call, done.

 
   // Called when a datatype (SyncableService) has a need for sync to start
   // ASAP, presumably because a local change event has occurred but we're