[ew] Move operation observers from QuotaUtil to FileSystemBackend.

storage/browser/fileapi/isolated_file_system_backend.cc

Index: storage/browser/fileapi/isolated_file_system_backend.cc
diff --git a/storage/browser/fileapi/isolated_file_system_backend.cc b/storage/browser/fileapi/isolated_file_system_backend.cc
index 90a0ce8861d1165766e0c47ab6e00deaca8f9f6e..3248994a95c99dbbdcf4375fc33938f76b91fedd 100644
--- a/storage/browser/fileapi/isolated_file_system_backend.cc
+++ b/storage/browser/fileapi/isolated_file_system_backend.cc
@@ -149,4 +149,19 @@ FileSystemQuotaUtil* IsolatedFileSystemBackend::GetQuotaUtil() {
   return NULL;
 }
 
+const UpdateObserverList* IsolatedFileSystemBackend::GetUpdateObservers(
+    FileSystemType type) const {
+  return NULL;
+}
+
+const ChangeObserverList* IsolatedFileSystemBackend::GetChangeObservers(
+    FileSystemType type) const {
+  return NULL;
+}
+
+const AccessObserverList* IsolatedFileSystemBackend::GetAccessObservers(
+    FileSystemType type) const {
+  return NULL;
+}
+
 }  // namespace storage