[fsp] Remember mounted file systems as soon as possible.

chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc

Index: chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
diff --git a/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc b/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
index c0cc6d6d40b670192e72c34455b82d737458f3fa..09e430a0e9cb241d741e0a5873128df29296f845 100644
--- a/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
+++ b/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
@@ -75,7 +75,8 @@ bool FileSystemProviderUnmountFunction::RunSync() {
     return false;
 
   if (!service->UnmountFileSystem(extension_id(),
-                                  params->options.file_system_id)) {
+                                  params->options.file_system_id,
+                                  Service::UNMOUNT_REASON_USER)) {
     // TODO(mtomasz): Pass more detailed errors, rather than just a bool.
     base::ListValue* result = new base::ListValue();
     result->Append(CreateError(kSecurityErrorName, kUnmountFailedErrorMessage));