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chrome/browser/net/file_downloader.h

 // Copyright 2015 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_NET_FILE_DOWNLOADER_H_
 #define CHROME_BROWSER_NET_FILE_DOWNLOADER_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 namespace net {
 class URLFetcher;
 class URLRequestContextGetter;
 }  // namespace net
 
 class GURL;
 
 // Helper class to download a file from a given URL and store it in a local
 // file. If |overwrite| is true, any existing file will be overwritten;
 // otherwise if the local file already exists, this will report success without
 // downloading anything.
 class FileDownloader : public net::URLFetcherDelegate {
  public:
-  typedef base::Callback<void(bool /* success */)> DownloadFinishedCallback;
+  enum Result {
+    // The file was successfully downloaded.
+    DOWNLOADED,
+    // A local file at the given path already existed and was kept.
+    EXISTS,
+    // Downloading failed.
+    FAILED
+  };
+  using DownloadFinishedCallback = base::Callback<void(Result)>;
 
   // Directly starts the download (if necessary) and runs |callback| when done.
   // If the instance is destroyed before it is finished, |callback| is not run.
   FileDownloader(const GURL& url,
                  const base::FilePath& path,
                  bool overwrite,
                  net::URLRequestContextGetter* request_context,
                  const DownloadFinishedCallback& callback);
   ~FileDownloader() override;
 
+  static bool IsSuccess(Result result) { return result != FAILED; }
+
  private:
   // net::URLFetcherDelegate implementation.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   void OnFileExistsCheckDone(bool exists);
 
   void OnFileMoveDone(bool success);
 
   DownloadFinishedCallback callback_;
 
   scoped_ptr<net::URLFetcher> fetcher_;
 
   base::FilePath local_path_;
 
   base::WeakPtrFactory<FileDownloader> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FileDownloader);
 };
 
 #endif  // CHROME_BROWSER_NET_FILE_DOWNLOADER_H_