Persist Directory to disk when the app is backgrounded.

chrome/browser/sync/glue/sync_backend_host_core.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/sync_backend_host_core.h"
 
 #include "base/files/file_util.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/sync/glue/device_info.h"
 #include "chrome/browser/sync/glue/invalidation_adapter.h"
 #include "chrome/browser/sync/glue/sync_backend_registrar.h"
 #include "chrome/browser/sync/glue/synced_device_tracker.h"
 #include "chrome/common/chrome_version_info.h"
 #include "components/invalidation/invalidation_util.h"
 #include "components/invalidation/object_id_invalidation_map.h"
 #include "sync/internal_api/public/events/protocol_event.h"
 #include "sync/internal_api/public/http_post_provider_factory.h"
 #include "sync/internal_api/public/internal_components_factory.h"
 #include "sync/internal_api/public/sessions/commit_counters.h"
 #include "sync/internal_api/public/sessions/status_counters.h"
 #include "sync/internal_api/public/sessions/sync_session_snapshot.h"
 #include "sync/internal_api/public/sessions/update_counters.h"
 #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
 // are multiple syncers involved.
 
 #define SLOG(severity) LOG(severity) << name_ << ": "
 
 #define SDVLOG(verbose_level) DVLOG(verbose_level) << name_ << ": "
 
 static const int kSaveChangesIntervalSeconds = 10;
@@ skipping 619 matching lines @@
 }
 
 void SyncBackendHostCore::DoRetryConfiguration(
     const base::Closure& retry_callback) {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   host_.Call(FROM_HERE,
              &SyncBackendHostImpl::RetryConfigurationOnFrontendLoop,
              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;
 
   if (sync_manager_) {
     // Grab our own copy of the buffered events.
     // The buffer is not modified by this operation.
     std::vector<syncer::ProtocolEvent*> buffered_events;
     sync_manager_->GetBufferedProtocolEvents().release(&buffered_events);
 
@@ skipping 81 matching lines @@
       base::TimeDelta::FromSeconds(kSaveChangesIntervalSeconds),
       this, &SyncBackendHostCore::SaveChanges);
 }
 
 void SyncBackendHostCore::SaveChanges() {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->SaveChanges();
 }
 
 }  // namespace browser_sync