Preview tab data source. (Sample CL)

chrome/browser/printing/print_preview_data_service.h

+// Copyright (c) 2011 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_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_
+#define CHROME_BROWSER_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_
+#pragma once
+
+#include <map>
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_memory.h"
+
+template<typename T> struct DefaultSingletonTraits;
+
+class PrintPreviewUI;
+
+// PrintPreviewDataService manages data for chrome://print requests.
+//
+// PrintPreviewDataService owns the data and is responsible for freeing it when
+// either:
+//    a) There is a new data.
+//    b) When PrintPreviewDataService is destroyed.
+//
+class PrintPreviewDataService {
+ public:
+  static PrintPreviewDataService* GetInstance();
+
+  // Get the data entry from PreviewDataSourceMap.
+  void GetDataEntry(PrintPreviewUI* preview_ui,
+                    scoped_refptr<RefCountedBytes>* data);
+
+  // Set/Update the data entry in PreviewDataSourceMap.
+  void SetDataEntry(PrintPreviewUI* preview_ui,
+                    const RefCountedBytes* data);
+
+  // Remove the corresponding PrintPreviewUI entry from the map.
+  void RemoveEntry(PrintPreviewUI* preview_ui);
+
+ private:
+  friend struct DefaultSingletonTraits<PrintPreviewDataService>;
+
+  // 1:1 relationship between PrintPreviewUI* and preview data.
+  // Key: Print preview UI address.
+  // Value: Preview data.
+  typedef std::map<PrintPreviewUI*, scoped_refptr<RefCountedBytes> >
+      PreviewDataSourceMap;
+
+  PrintPreviewDataService();
+  virtual ~PrintPreviewDataService();
+
+  PreviewDataSourceMap data_src_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewDataService);
+};
+
+#endif  // CHROME_BROWSER_PRINTING_PRINT_PREVIEW_DATA_SERVICE_H_