[SyncFS] Drop PostTaskAndReply from LocalToRemoteSyncer (5)

chrome/browser/sync_file_system/drive_backend/drive_backend_util.h

Index: chrome/browser/sync_file_system/drive_backend/drive_backend_util.h
diff --git a/chrome/browser/sync_file_system/drive_backend/drive_backend_util.h b/chrome/browser/sync_file_system/drive_backend/drive_backend_util.h
index 30805028c8986ad21e26a7ca6d2a1e323de1b58e..d2045160cff5db67032c071770b04294478cb79d 100644
--- a/chrome/browser/sync_file_system/drive_backend/drive_backend_util.h
+++ b/chrome/browser/sync_file_system/drive_backend/drive_backend_util.h
@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "base/bind.h"
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/sync_file_system/drive_backend/metadata_database.pb.h"
@@ -83,6 +85,19 @@ const typename Container::mapped_type& LookUpMap(
   return found->second;
 }
 
+template <typename R, typename S, typename T>
+R ComposeFunction(const base::Callback<T()>& g,
+                  const base::Callback<R(S)>& f) {
+  return f.Run(g.Run());
+}
+
+template <typename R, typename S, typename T>
+base::Callback<R()> CreateComposedFunction(
+    const base::Callback<T()>& g,
+    const base::Callback<R(S)>& f) {
+  return base::Bind(&ComposeFunction<R, S, T>, g, f);
+}
+
 }  // namespace drive_backend
 }  // namespace sync_file_system