Created an interface for DownloadFile, for use in unit tests.

content/browser/download/download_file_impl.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_DOWNLOAD_FILE_IMPL_H_
+#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_
+#pragma once
+
+#include "content/browser/download/download_file.h"
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "content/browser/download/download_request_handle.h"
+#include "content/common/content_export.h"
+
+struct DownloadCreateInfo;
+class DownloadManager;
+
+class CONTENT_EXPORT DownloadFileImpl : virtual public DownloadFile {
+ public:
+  // Takes ownership of the object pointed to by |request_handle|.
+  DownloadFileImpl(const DownloadCreateInfo* info,
+                   DownloadRequestHandleInterface* request_handle,
+                   DownloadManager* download_manager);
+  virtual ~DownloadFileImpl();
+
+  // DownloadFile functions.
+  virtual net::Error Initialize(bool calculate_hash) OVERRIDE;
+  virtual net::Error AppendDataToFile(const char* data,
+                                      size_t data_len) OVERRIDE;
+  virtual net::Error Rename(const FilePath& full_path) OVERRIDE;
+  virtual void Detach() OVERRIDE;
+  virtual void Cancel() OVERRIDE;
+  virtual void Finish() OVERRIDE;
+  virtual void AnnotateWithSourceInformation() OVERRIDE;
+  virtual FilePath FullPath() const OVERRIDE;
+  virtual bool InProgress() const OVERRIDE;
+  virtual int64 BytesSoFar() const OVERRIDE;
+  virtual bool GetSha256Hash(std::string* hash) OVERRIDE;
+  virtual void CancelDownloadRequest() OVERRIDE;
+  virtual int Id() const OVERRIDE;
+  virtual DownloadManager* GetDownloadManager() OVERRIDE;
+  virtual const DownloadId& GlobalId() const OVERRIDE;
+  virtual std::string DebugString() const OVERRIDE;
+
+ private:
+  // The base file instance.
+  BaseFile file_;
+
+  // The unique identifier for this download, assigned at creation by
+  // the DownloadFileManager for its internal record keeping.
+  DownloadId id_;
+
+  // The handle to the request information.  Used for operations outside the
+  // download system, specifically canceling a download.
+  scoped_ptr<DownloadRequestHandleInterface> request_handle_;
+
+  // DownloadManager this download belongs to.
+  scoped_refptr<DownloadManager> download_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadFileImpl);
+};
+
+#endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_