Download code cleanup patch of death:

chrome/browser/download/download_history.h

Index: chrome/browser/download/download_history.h
diff --git a/chrome/browser/download/download_history.h b/chrome/browser/download/download_history.h
new file mode 100644
index 0000000000000000000000000000000000000000..3fe789ef1742cdfb4aee304412bcac93c42f293c
--- /dev/null
+++ b/chrome/browser/download/download_history.h
@@ -0,0 +1,91 @@
+// Copyright (c) 2010 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_DOWNLOAD_DOWNLOAD_HISTORY_H_
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
+#pragma once
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "chrome/browser/cancelable_request.h"
+#include "chrome/browser/history/history.h"
+
+class DownloadItem;
+class Profile;
+
+namespace base {
+class Time;
+}
+
+// Interacts with the HistoryService on behalf of the download subsystem.
+class DownloadHistory {
+ public:
+  // Converts history database handles to download items.
+  class DownloadItemMapper {
+   public:
+    virtual ~DownloadItemMapper() {}
+
+    // Returns a DownloadItem* corresponding to |db_handle|, or NULL if no such
+    // DownloadItem exists.
+    virtual DownloadItem* GetDownloadItemFromDbHandle(int64 db_handle) = 0;
+  };
+
+  // A fake download table ID which represents a download that has started,
+  // but is not yet in the table.
+  static const int kUninitializedHandle;
+
+  typedef Callback1<std::vector<DownloadItem*> >::Type DownloadSearchCallback;
+
+  DownloadHistory(Profile* profile, DownloadItemMapper* mapper);
+
+  // Retrieves DownloadCreateInfos saved in the history.
+  void Load(HistoryService::DownloadQueryCallback* callback);
+
+  // Starts a history search for downloads and invokes |callback| when done.
+  void Search(const string16& query,
+              DownloadSearchCallback* callback);
+
+  // Adds a new entry for a download to the history database.
+  void AddEntry(const DownloadCreateInfo& info,
+                DownloadItem* download_item,
+                HistoryService::DownloadCreateCallback* callback);
+
+  // Updates the history entry for |download_item|.
+  void UpdateEntry(DownloadItem* download_item);
+
+  // Updates the download path for |download_item| to |new_path|.
+  void UpdateDownloadPath(DownloadItem* download_item,
+                          const FilePath& new_path);
+
+  // Removes |download_item| from the history database.
+  void RemoveEntry(DownloadItem* download_item);
+
+  // Removes download-related history entries in the given time range.
+  void RemoveEntriesBetween(const base::Time remove_begin,
+                            const base::Time remove_end);
+
+  // Returns a new unique database handle which will not collide with real ones.
+  int64 GetNextFakeDbHandle();
+
+ private:
+  void OnSearchDownloadsComplete(HistoryService::Handle handle,
+                                 std::vector<int64>* results);
+
+  Profile* profile_;
+
+  // In case we don't have a valid db_handle, we use |fake_db_handle_| instead.
+  // This is useful for incognito mode or when the history database is offline.
+  // Downloads are expected to have unique handles, so we decrement the next
+  // fake handle value on every use.
+  int64 next_fake_db_handle_;
+
+  DownloadItemMapper* download_item_mapper_;
+
+  CancelableRequestConsumerTSimple<DownloadSearchCallback*> history_consumer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadHistory);
+};
+
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_