Refactor the interface for the CrxDownloader to take a callback.

chrome/browser/component_updater/url_fetcher_downloader.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/component_updater/url_fetcher_downloader.h"
 
 #include "chrome/browser/component_updater/component_updater_utils.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/url_fetcher.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
 
 namespace component_updater {
 
 UrlFetcherDownloader::UrlFetcherDownloader(
     scoped_ptr<CrxDownloader> successor,
     net::URLRequestContextGetter* context_getter,
-    scoped_refptr<base::SequencedTaskRunner> task_runner,
-    const DownloadCallback& download_callback)
-    : CrxDownloader(successor.Pass(), download_callback),
+    scoped_refptr<base::SequencedTaskRunner> task_runner)
+    : CrxDownloader(successor.Pass()),
       context_getter_(context_getter),
       task_runner_(task_runner),
       downloaded_bytes_(-1),
       total_bytes_(-1) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
 UrlFetcherDownloader::~UrlFetcherDownloader() {}
 
 void UrlFetcherDownloader::DoStartDownload(const GURL& url) {
@@ skipping 53 matching lines @@
     const net::URLFetcher* source,
     int64 current,
     int64 total) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   downloaded_bytes_ = current;
   total_bytes_ = total;
 }
 
 }  // namespace component_updater