[SyncFS] Improve debug logs of MetadataDatabaseIndex

chrome/browser/sync_file_system/drive_backend/metadata_database.cc

 // 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.
 
 #include "chrome/browser/sync_file_system/drive_backend/metadata_database.h"
 
 #include <algorithm>
 #include <stack>
 
 #include "base/bind.h"
@@ skipping 1087 matching lines @@
 bool MetadataDatabase::GetNormalPriorityDirtyTracker(
     FileTracker* tracker) const {
   DirtyTrackers::const_iterator itr = dirty_trackers_.begin();
   if (itr == dirty_trackers_.end())
     return false;
   if (tracker)
     *tracker = **itr;
   return true;
 }
 
-bool MetadataDatabase::GetLowPriorityDirtyTracker(
-    FileTracker* tracker) const {
-  DirtyTrackers::const_iterator itr = low_priority_dirty_trackers_.begin();
-  if (itr == low_priority_dirty_trackers_.end())
-    return false;
-  if (tracker)
-    *tracker = **itr;
-  return true;
+bool MetadataDatabase::HasLowPriorityDirtyTracker() const {
+  return !low_priority_dirty_trackers_.empty();
 }
 
 bool MetadataDatabase::HasDirtyTracker() const {
   return CountDirtyTracker() != 0;
 }
 
 size_t MetadataDatabase::CountDirtyTracker() const {
   return dirty_trackers_.size() + low_priority_dirty_trackers_.size();
 }
 
@@ skipping 940 matching lines @@
     MakeTrackerActive(tracker->tracker_id(), batch);
     ClearDirty(tracker, batch);
     return;
   }
 
   NOTREACHED();
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system