Remove unused constant history::kThumbnailsFilename.

components/history/core/browser/history_backend.cc

 // Copyright (c) 2012 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 "components/history/core/browser/history_backend.h"
 
 #include <algorithm>
 #include <functional>
 #include <list>
 #include <map>
@@ skipping 262 matching lines @@
 #if defined(OS_IOS)
 void HistoryBackend::PersistState() {
   Commit();
 }
 #endif
 
 void HistoryBackend::ClearCachedDataForContextID(ContextID context_id) {
   tracker_.ClearCachedDataForContextID(context_id);
 }
 
-base::FilePath HistoryBackend::GetThumbnailFileName() const {
-  return history_dir_.Append(kThumbnailsFilename);
-}
-
 base::FilePath HistoryBackend::GetFaviconsFileName() const {
   return history_dir_.Append(kFaviconsFilename);
 }
 
 SegmentID HistoryBackend::GetLastSegmentID(VisitID from_visit) {
   // Set is used to detect referrer loops.  Should not happen, but can
   // if the database is corrupt.
   std::set<VisitID> visit_set;
   VisitID visit_id = from_visit;
   while (visit_id) {
@@ skipping 2268 matching lines @@
 }
 
 bool HistoryBackend::ClearAllThumbnailHistory(
     const std::vector<GURL>& kept_urls) {
   if (!thumbnail_db_) {
     // When we have no reference to the thumbnail database, maybe there was an
     // error opening it. In this case, we just try to blow it away to try to
     // fix the error if it exists. This may fail, in which case either the
     // file doesn't exist or there's no more we can do.
     sql::Connection::Delete(GetFaviconsFileName());
-
-    // Older version of the database.
-    sql::Connection::Delete(GetThumbnailFileName());
     return true;
   }
 
   // Isolate from any long-running transaction.
   thumbnail_db_->CommitTransaction();
   thumbnail_db_->BeginTransaction();
 
   // TODO(shess): If this fails, perhaps the database should be razed
   // or deleted.
   if (!thumbnail_db_->RetainDataForPageUrls(kept_urls)) {
@@ skipping 41 matching lines @@
   // transaction is currently open.
   db_->CommitTransaction();
   db_->Vacuum();
   db_->BeginTransaction();
   db_->GetStartDate(&first_recorded_time_);
 
   return true;
 }
 
 }  // namespace history