[SyncFS] Make ExtensionService usage of SyncWorker asynchronous

chrome/browser/sync_file_system/drive_backend/callback_helper.h

Index: chrome/browser/sync_file_system/drive_backend/callback_helper.h
diff --git a/chrome/browser/sync_file_system/drive_backend/callback_helper.h b/chrome/browser/sync_file_system/drive_backend/callback_helper.h
index 2dd97964a52d9aea78af4fac4b015f44a597649a..b5fd9e45f5eb496059f94081ac242b68fe17e5e4 100644
--- a/chrome/browser/sync_file_system/drive_backend/callback_helper.h
+++ b/chrome/browser/sync_file_system/drive_backend/callback_helper.h
@@ -30,6 +30,10 @@ RebindForward(T& t) {
   return t;
 }
 
+void RelayToTaskRunner0(base::SequencedTaskRunner* task_runner,

[peria, 2014/04/24 02:38:21]

This declaration is not needed.

[tzik, 2014/04/24 06:56:55]

Refactored in another CL.

+                        const tracked_objects::Location& from_here,
+                        const base::Callback<void()>& callback);
+
 template <typename T>
 void RelayToTaskRunner1(base::SequencedTaskRunner* task_runner,
                         const tracked_objects::Location& from_here,
@@ -53,6 +57,9 @@ void RelayToTaskRunner2(base::SequencedTaskRunner* task_runner,
 
 }  // namespace internal
 
+base::Callback<void()> CreateRelayedCallback(
+    const base::Callback<void()>& callback);
+
 template <typename T>
 base::Callback<void(T)> CreateRelayedCallback(
     const base::Callback<void(T)>& callback) {