Persist Directory to disk when the app is backgrounded.

chrome/browser/sync/glue/sync_backend_host_core.h

Index: chrome/browser/sync/glue/sync_backend_host_core.h
diff --git a/chrome/browser/sync/glue/sync_backend_host_core.h b/chrome/browser/sync/glue/sync_backend_host_core.h
index 46fb599e96bc4361854a049102df6ebcc8f98c28..4915f0d831c9d0345018fbac1891a00b9a67d1d4 100644
--- a/chrome/browser/sync/glue/sync_backend_host_core.h
+++ b/chrome/browser/sync/glue/sync_backend_host_core.h
@@ -239,6 +239,11 @@ class SyncBackendHostCore
       base::Callback<void(const std::vector<syncer::ModelType>& type,
                           ScopedVector<base::ListValue>) > callback);
 
+  // Tell the sync manager to persist its state by writing to disk.
+  // Called on the sync thread, both by a timer and, on Android, when the
+  // application is backgrounded.
+  void SaveChanges();
+
  private:
   friend class base::RefCountedThreadSafe<SyncBackendHostCore>;
   friend class SyncBackendHostForProfileSyncTest;
@@ -251,13 +256,6 @@ class SyncBackendHostCore
   // be run on; the host's |registrar_->sync_thread()|.
   void StartSavingChanges();
 
-  // Invoked periodically to tell the syncapi to persist its state
-  // by writing to disk.
-  // This is called from the thread we were created on (which is sync thread),
-  // using a repeating timer that is kicked off as soon as the SyncManager
-  // tells us it completed initialization.
-  void SaveChanges();
-
   // Name used for debugging.
   const std::string name_;