[SyncFS] Improve debug logs of MetadataDatabaseIndex

chrome/browser/sync_file_system/drive_backend/metadata_database.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 325 matching lines @@
 
   // Changes the priority of the tracker to low.
   void LowerTrackerPriority(int64 tracker_id);
   void PromoteLowerPriorityTrackersToNormal();
 
   // 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;
 
   // Returns true if there is a low priority dirty tracker.
-  // Assigns the dirty tracker if exists and |tracker| is non-NULL.
-  bool GetLowPriorityDirtyTracker(FileTracker* tracker) const;
+  bool HasLowPriorityDirtyTracker() const;
 
   bool HasDirtyTracker() const;
   size_t CountDirtyTracker() const;
   size_t CountFileMetadata() const;
   size_t CountFileTracker() const;
 
   bool GetMultiParentFileTrackers(std::string* file_id,
                                   TrackerIDSet* trackers);
   bool GetConflictingTrackers(TrackerIDSet* trackers);
 
@@ skipping 151 matching lines @@
 
   base::WeakPtrFactory<MetadataDatabase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MetadataDatabase);
 };
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_