Disassociate argument type from return type in PostTaskAndReplyWithResult template.

base/file_util_proxy.cc

Index: base/file_util_proxy.cc
diff --git a/base/file_util_proxy.cc b/base/file_util_proxy.cc
index 290279ef3e20823760e72ed3fefb5abc5a8b7246..a193b4bc00d6b801dc125f68724a0e4e2ac55095 100644
--- a/base/file_util_proxy.cc
+++ b/base/file_util_proxy.cc
@@ -405,8 +405,13 @@ bool FileUtilProxy::RelayFileTask(
     const tracked_objects::Location& from_here,
     const FileTask& file_task,
     const StatusCallback& callback) {
-  return base::PostTaskAndReplyWithResult(
-      task_runner, from_here, file_task, callback);
+  if (callback.is_null()) {
+    return task_runner->PostTask(from_here,
+                                 base::Bind(base::IgnoreResult(file_task)));
+  } else {
+    return base::PostTaskAndReplyWithResult(task_runner, from_here, file_task,
+                                            callback);
+  }
 }
 
 // static