[SyncFS] Rephrase "LowerPriority" to "Demoted" in MetadataDatabase

chrome/browser/sync_file_system/drive_backend/metadata_database.h

Index: chrome/browser/sync_file_system/drive_backend/metadata_database.h
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database.h b/chrome/browser/sync_file_system/drive_backend/metadata_database.h
index 99e967b00e82e5d17cf528e31dd85f74af3bfede..07c5b3ae2f8c5f3be9d28bd8cf1cdf344df2c937 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database.h
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database.h
@@ -322,17 +322,16 @@ class MetadataDatabase {
                                       const SyncStatusCallback& callback);
 
   // Changes the priority of the tracker to low.
-  void LowerTrackerPriority(int64 tracker_id);
-  bool PromoteLowerPriorityTrackersToNormal();
-
+  void DemoteTracker(int64 tracker_id);
+  bool PromoteDemotedTrackers();
   void PromoteDemotedTracker(int64 tracker_id);
 
   // Returns true if there is a normal priority dirty tracker.
   // Assigns the dirty tracker if exists and |tracker| is non-NULL.
-  bool GetNormalPriorityDirtyTracker(FileTracker* tracker) const;
+  bool GetDirtyTracker(FileTracker* tracker) const;
 
   // Returns true if there is a low priority dirty tracker.
-  bool HasLowPriorityDirtyTracker() const;
+  bool HasDemotedDirtyTracker() const;
 
   bool HasDirtyTracker() const;
   size_t CountDirtyTracker() const;