[SyncFS] Improve debug logs of MetadataDatabaseIndex

chrome/browser/sync_file_system/drive_backend/metadata_database_index.h

Index: chrome/browser/sync_file_system/drive_backend/metadata_database_index.h
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database_index.h b/chrome/browser/sync_file_system/drive_backend/metadata_database_index.h
index e37c50e78348a436abb8ad69830060b7c5696985..581f790b1f4d21d42173094868482a67674cb93e 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database_index.h
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database_index.h
@@ -92,6 +92,8 @@ class MetadataDatabaseIndex {
       int64 parent_tracker_id,
       const std::string& title) const;
 
+  std::vector<int64> GetFileTrackerIDsByParent(int64 parent_tracker_id) const;
+
   // Returns the |file_id| of a file that has multiple trackers.
   std::string PickMultiTrackerFileID() const;
 
@@ -106,9 +108,13 @@ class MetadataDatabaseIndex {
   // Demotes a dirty tracker.
   void DemoteDirtyTracker(int64 tracker_id);
 
+  bool HasDemotedDirtyTracker() const;
+
   // Promotes all demoted dirty trackers to normal dirty trackers.
   void PromoteDemotedDirtyTrackers();
 
+  std::vector<std::string> GetRegisteredAppIDs() const;
+
  private:
   typedef base::ScopedPtrHashMap<std::string, FileMetadata> MetadataByID;
   typedef base::ScopedPtrHashMap<int64, FileTracker> TrackerByID;