Move Singleton and related structs to namespace base

chrome/browser/printing/print_preview_data_service.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 "chrome/browser/printing/print_preview_data_service.h"
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/singleton.h"
 #include "base/stl_util.h"
 #include "printing/print_job_constants.h"
@@ skipping 62 matching lines @@
             index < printing::FIRST_PAGE_INDEX);
   }
 
   PreviewPageDataMap page_data_map_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintPreviewDataStore);
 };
 
 // static
 PrintPreviewDataService* PrintPreviewDataService::GetInstance() {
-  return Singleton<PrintPreviewDataService>::get();
+  return base::Singleton<PrintPreviewDataService>::get();
 }
 
 PrintPreviewDataService::PrintPreviewDataService() {
 }
 
 PrintPreviewDataService::~PrintPreviewDataService() {
 }
 
 void PrintPreviewDataService::GetDataEntry(
     int32_t preview_ui_id,
@@ skipping 17 matching lines @@
 
 void PrintPreviewDataService::RemoveEntry(int32_t preview_ui_id) {
   data_store_map_.erase(preview_ui_id);
 }
 
 int PrintPreviewDataService::GetAvailableDraftPageCount(int32_t preview_ui_id) {
   PreviewDataStoreMap::const_iterator it = data_store_map_.find(preview_ui_id);
   return (it == data_store_map_.end()) ?
       0 : it->second->GetAvailableDraftPageCount();
 }