Make DownloadItem derive SupportsUserData instead of re-implementing it.

content/public/browser/download_item.h

 // 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.
 //
 // Each download is represented by a DownloadItem, and all DownloadItems
 // are owned by the DownloadManager which maintains a global list of all
 // downloads. DownloadItems are created when a user initiates a download,
 // and exist for the duration of the browser life time.
 //
 // Download observers:
 //   DownloadItem::Observer:
 //     - allows observers to receive notifications about one download from start
 //       to completion
 // Use AddObserver() / RemoveObserver() on the appropriate download object to
 // receive state updates.
 
 #ifndef CONTENT_PUBLIC_BROWSER_DOWNLOAD_ITEM_H_
 #define CONTENT_PUBLIC_BROWSER_DOWNLOAD_ITEM_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/string16.h"
+#include "base/supports_user_data.h"
 #include "content/public/browser/download_danger_type.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/common/page_transition_types.h"
 
 class FilePath;
 class GURL;
 struct DownloadCreateInfo;
 
 namespace base {
 class Time;
 class TimeDelta;
 }
 
 namespace content {
 
 class BrowserContext;
 class DownloadId;
 class DownloadManager;
 class WebContents;
 struct DownloadPersistentStoreInfo;
 
 // One DownloadItem per download. This is the model class that stores all the
 // state for a download. Multiple views, such as a tab's download shelf and the
 // Destination tab's download view, may refer to a given DownloadItem.
 //
 // This is intended to be used only on the UI thread.
-class CONTENT_EXPORT DownloadItem {
+class CONTENT_EXPORT DownloadItem : public base::SupportsUserData {
  public:
   enum DownloadState {
     // Download is actively progressing.
     IN_PROGRESS = 0,
 
     // Download is completely finished.
     COMPLETE,
 
     // Download has been cancelled.
     CANCELLED,
@@ skipping 41 matching lines @@
    public:
     virtual void OnDownloadUpdated(DownloadItem* download) = 0;
 
     // Called when a downloaded file has been opened.
     virtual void OnDownloadOpened(DownloadItem* download) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
-  // Interface for data that can be stored associated with (and owned
-  // by) an object of this class via GetExternalData/SetExternalData.
-  class ExternalData {
-   public:
-    virtual ~ExternalData() {};
-  };
-
   virtual ~DownloadItem() {}
 
   virtual void AddObserver(DownloadItem::Observer* observer) = 0;
   virtual void RemoveObserver(DownloadItem::Observer* observer) = 0;
 
   // Notifies our observers periodically.
   virtual void UpdateObservers() = 0;
 
   // Returns true if it is OK to open a folder which this file is inside.
   virtual bool CanShowInFolder() = 0;
@@ skipping 153 matching lines @@
   // Set a display name for the download that will be independent of the target
   // filename. If |name| is not empty, then GetFileNameToReportUser() will
   // return |name|. Has no effect on the final target filename.
   virtual void SetDisplayName(const FilePath& name) = 0;
 
   // Returns the user-verified target file path for the download.
   // This returns the same path as GetTargetFilePath() for safe downloads
   // but does not for dangerous downloads until the name is verified.
   virtual FilePath GetUserVerifiedFilePath() const = 0;
 
-  // Manage data owned by other subsystems associated with the
-  // DownloadItem.  By custom, key is the address of a
-  // static char subsystem_specific_string[] = ".."; defined
-  // in the subsystem, but the only requirement of this interface
-  // is that the key be unique over all data stored with this
-  // DownloadItem.
-  //
-  // Note that SetExternalData takes ownership of the
-  // passed object; it will be destroyed when the DownloadItem is.
-  // If an object is already held by the DownloadItem associated with
-  // the passed key, it will be destroyed if overwriten by a new pointer
-  // (overwrites by the same pointer are ignored).
-  virtual       ExternalData* GetExternalData(const void* key) = 0;
-  virtual const ExternalData* GetExternalData(const void* key) const = 0;
-  virtual void SetExternalData(const void* key, ExternalData* data) = 0;
-
   virtual std::string DebugString(bool verbose) const = 0;
 
   virtual void MockDownloadOpenForTesting() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_DOWNLOAD_ITEM_H_