[ew] Move operation observers from QuotaUtil to FileSystemBackend.

chrome/browser/chromeos/fileapi/file_system_backend.cc

Index: chrome/browser/chromeos/fileapi/file_system_backend.cc
diff --git a/chrome/browser/chromeos/fileapi/file_system_backend.cc b/chrome/browser/chromeos/fileapi/file_system_backend.cc
index 52975e5ece3a58fe9f0af7af981e4f9dbeb57356..1b0ac44e096c3873c606652dc216e69f613ddcea 100644
--- a/chrome/browser/chromeos/fileapi/file_system_backend.cc
+++ b/chrome/browser/chromeos/fileapi/file_system_backend.cc
@@ -145,6 +145,21 @@ storage::FileSystemQuotaUtil* FileSystemBackend::GetQuotaUtil() {
   return NULL;
 }
 
+const storage::UpdateObserverList* FileSystemBackend::GetUpdateObservers(
+    storage::FileSystemType type) const {
+  return NULL;
+}
+
+const storage::ChangeObserverList* FileSystemBackend::GetChangeObservers(
+    storage::FileSystemType type) const {
+  return NULL;
+}
+
+const storage::AccessObserverList* FileSystemBackend::GetAccessObservers(
+    storage::FileSystemType type) const {
+  return NULL;
+}
+
 bool FileSystemBackend::IsAccessAllowed(
     const storage::FileSystemURL& url) const {
   if (!url.is_valid())