Created a DownloadManager interface, for use in unit tests..

content/browser/download/mock_download_manager.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 CONTENT_BROWSER_DOWNLOAD_MOCK_DOWNLOAD_MANAGER_H_
 #define CONTENT_BROWSER_DOWNLOAD_MOCK_DOWNLOAD_MANAGER_H_
 #pragma once
 
 #include "content/browser/download/download_manager.h"
+#include "content/browser/download/download_id.h"
 
 class DownloadStatusUpdater;
 class DownloadItem;
 
 class MockDownloadManager : public DownloadManager {
  public:
   explicit MockDownloadManager(content::DownloadManagerDelegate* delegate,
                                DownloadIdFactory* id_factory,
-                               DownloadStatusUpdater* updater)
-      : DownloadManager(delegate, id_factory, updater) {
-  }
+                               DownloadStatusUpdater* updater);
+  virtual ~MockDownloadManager();
 
-  // Override some functions.
-  virtual void UpdateHistoryForDownload(DownloadItem*) { }
+  // DownloadManager:
+  virtual void Shutdown() OVERRIDE;
+  virtual void GetTemporaryDownloads(const FilePath& dir_path,
+                                     DownloadVector* result) OVERRIDE;
+  virtual void GetAllDownloads(const FilePath& dir_path,
+                               DownloadVector* result) OVERRIDE;
+  virtual void SearchDownloads(const string16& query,
+                               DownloadVector* result) OVERRIDE;
+  virtual bool Init(content::BrowserContext* browser_context) OVERRIDE;
+  virtual void StartDownload(int32 id) OVERRIDE;
+  virtual void UpdateDownload(int32 download_id, int64 size) OVERRIDE;
+  virtual void OnResponseCompleted(int32 download_id, int64 size,
+                                   const std::string& hash) OVERRIDE;
+  virtual void CancelDownload(int32 download_id) OVERRIDE;
+  virtual void OnDownloadInterrupted(int32 download_id, int64 size,
+                                     InterruptReason reason) OVERRIDE;
+  virtual void DownloadCancelledInternal(DownloadItem* download) OVERRIDE;
+  virtual void RemoveDownload(int64 download_handle) OVERRIDE;
+  virtual bool IsDownloadReadyForCompletion(DownloadItem* download) OVERRIDE;
+  virtual void MaybeCompleteDownload(DownloadItem* download) OVERRIDE;
+  virtual void OnDownloadRenamedToFinalName(int download_id,
+                                            const FilePath& full_path,
+                                            int uniquifier) OVERRIDE;
+  virtual int RemoveDownloadsBetween(const base::Time remove_begin,
+                                     const base::Time remove_end) OVERRIDE;
+  virtual int RemoveDownloads(const base::Time remove_begin) OVERRIDE;
+  virtual int RemoveAllDownloads() OVERRIDE;
+  virtual void DownloadCompleted(int32 download_id) OVERRIDE;
+  virtual void DownloadUrl(const GURL& url,
+                           const GURL& referrer,
+                           const std::string& referrer_encoding,
+                           TabContents* tab_contents) OVERRIDE;
+  virtual void DownloadUrlToFile(const GURL& url,
+                                 const GURL& referrer,
+                                 const std::string& referrer_encoding,
+                                 const DownloadSaveInfo& save_info,
+                                 TabContents* tab_contents) OVERRIDE;
+  virtual void AddObserver(Observer* observer) OVERRIDE;
+  virtual void RemoveObserver(Observer* observer) OVERRIDE;
+  virtual void OnPersistentStoreQueryComplete(
+      std::vector<DownloadPersistentStoreInfo>* entries) OVERRIDE;
+  virtual void OnItemAddedToPersistentStore(int32 download_id,
+                                            int64 db_handle) OVERRIDE;
+  virtual void ShowDownloadInBrowser(DownloadItem* download) OVERRIDE;
+  virtual int InProgressCount() const OVERRIDE;
+  virtual content::BrowserContext* BrowserContext() OVERRIDE;
+  virtual FilePath LastDownloadPath() OVERRIDE;
+  virtual void CreateDownloadItem(
+      DownloadCreateInfo* info,
+      const DownloadRequestHandle& request_handle) OVERRIDE;
+  virtual void ClearLastDownloadPath() OVERRIDE;
+  virtual void FileSelected(const FilePath& path, void* params) OVERRIDE;
+  virtual void FileSelectionCanceled(void* params) OVERRIDE;
+  virtual void RestartDownload(int32 download_id) OVERRIDE;
+  virtual void MarkDownloadOpened(DownloadItem* download) OVERRIDE;
+  virtual void CheckForHistoryFilesRemoval() OVERRIDE;
+  virtual void CheckForFileRemoval(DownloadItem* download_item) OVERRIDE;
+  virtual void AssertQueueStateConsistent(DownloadItem* download) OVERRIDE;
+  virtual DownloadItem* GetDownloadItem(int id) OVERRIDE;
+  virtual void SavePageDownloadStarted(DownloadItem* download) OVERRIDE;
+  virtual void SavePageDownloadFinished(DownloadItem* download) OVERRIDE;
+  virtual DownloadItem* GetActiveDownloadItem(int id) OVERRIDE;
+  virtual content::DownloadManagerDelegate* delegate() const OVERRIDE;
+  virtual void SetDownloadManagerDelegate(
+      content::DownloadManagerDelegate* delegate) OVERRIDE;
+  virtual DownloadId GetNextId() OVERRIDE;
+  virtual void ContinueDownloadWithPath(DownloadItem* download,
+                                        const FilePath& chosen_file) OVERRIDE;
+  virtual DownloadItem* GetActiveDownload(int32 download_id) OVERRIDE;
+  virtual void SetFileManager(DownloadFileManager* file_manager) OVERRIDE;
+
+private:
+  content::DownloadManagerDelegate* delegate_;
+  DownloadIdFactory* id_factory_;
+  DownloadStatusUpdater* updater_;
+  DownloadFileManager* file_manager_;
+  std::map<int32, DownloadItem*> item_map_;
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_MOCK_DOWNLOAD_MANAGER_H_