Use GData WAPI for FastFetch even if Drive API v2 is enabled.

chrome/browser/chromeos/drive/change_list_loader.h

Index: chrome/browser/chromeos/drive/change_list_loader.h
diff --git a/chrome/browser/chromeos/drive/change_list_loader.h b/chrome/browser/chromeos/drive/change_list_loader.h
index 107b6e95c120605cad7f7c7625bffee081998413..72b453cc1cb49b36dfb4faf4b5798f130733df62 100644
--- a/chrome/browser/chromeos/drive/change_list_loader.h
+++ b/chrome/browser/chromeos/drive/change_list_loader.h
@@ -281,6 +281,9 @@ class ChangeListLoader {
   // changestamp is up-to-date for fast fetch.
   int64 last_known_remote_changestamp_;
 
+  // The cache of the root_folder_id.
+  std::string root_folder_id_;
+
   // True if the full resource list is loaded (i.e. the resource metadata is
   // stored locally).
   bool loaded_;