Persist Directory to disk when the app is backgrounded.

chrome/browser/sync/glue/sync_backend_host_core.cc

Index: chrome/browser/sync/glue/sync_backend_host_core.cc
diff --git a/chrome/browser/sync/glue/sync_backend_host_core.cc b/chrome/browser/sync/glue/sync_backend_host_core.cc
index 2a78040131e0e7894375a1f11fa40c2e0285eb66..ff5a09962f2c987061b5e67e72e4bc0fd71eb893 100644
--- a/chrome/browser/sync/glue/sync_backend_host_core.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_core.cc
@@ -23,6 +23,7 @@
 #include "sync/internal_api/public/sync_context_proxy.h"
 #include "sync/internal_api/public/sync_manager.h"
 #include "sync/internal_api/public/sync_manager_factory.h"
+#include "sync/syncable/directory.h"
 #include "url/gurl.h"
 
 // Helper macros to log with the syncer thread name; useful when there
@@ -662,6 +663,15 @@ void SyncBackendHostCore::DoRetryConfiguration(
              retry_callback);
 }
 
+void SyncBackendHostCore::DoFlushDirectory() {
+  DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
+  syncer::syncable::Directory* directory =

[Nicolas Zea, 2014/09/15 22:38:59]

What will this do if the SBH isn't initialized yet? Should we let it crash or
just do nothing?

[maxbogue, 2014/09/16 15:34:31]

Which part will currently crash? How would the call even get to this point if
things aren't initialized?

[Nicolas Zea, 2014/09/18 16:52:17]

The SyncManager is only created when DoInitialize is called. It's possible for
the core to exist without DoInitialize having been called, and therefore the
SyncManager having been created.

As far as I can tell nowhere higher up in the callstack is it verified that the
backend has been initialized right?

[maxbogue, 2014/09/22 17:23:25]

Fixed this in PSS.

+      sync_manager()->GetUserShare()->directory.get();
+  if (directory != NULL) {
+    directory->SaveChanges();
+  }
+}
+
 void SyncBackendHostCore::SendBufferedProtocolEventsAndEnableForwarding() {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   forward_protocol_events_ = true;