Added support for multiple urls in the component updater.

chrome/browser/component_updater/crx_downloader.h

 // 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.
 
 #ifndef CHROME_BROWSER_COMPONENT_UPDATER_CRX_DOWNLOADER_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_CRX_DOWNLOADER_H_
 
 #include <vector>
 #include "base/basictypes.h"
 #include "base/callback.h"
@@ skipping 64 matching lines @@
   // chain of responsibility. |is_background_download| specifies that a
   // background downloader be used, if the platform supports it.
   static CrxDownloader* Create(
       bool is_background_download,
       net::URLRequestContextGetter* context_getter,
       scoped_refptr<base::SequencedTaskRunner> task_runner,
       const DownloadCallback& download_callback);
   virtual ~CrxDownloader();
 
   // Starts the download. One instance of the class handles one download only.
-  // Returns true if success or false in case of errors. One instance of
-  // CrxDownloader can only be started once, otherwise the behavior is
-  // undefined.
-  bool StartDownloadFromUrl(const GURL& url);
-  bool StartDownload(const std::vector<GURL>& urls);
+  // One instance of CrxDownloader can only be started once, otherwise the
+  // behavior is undefined. The callback gets invoked if the download can't
+  // be started.
+  void StartDownloadFromUrl(const GURL& url);
+  void StartDownload(const std::vector<GURL>& urls);
 
   const std::vector<DownloadMetrics> download_metrics() const;
 
  protected:
   CrxDownloader(scoped_ptr<CrxDownloader> successor,
                 const DownloadCallback& download_callback);
 
   // Handles the fallback in the case of multiple urls and routing of the
   // download to the following successor in the chain. Derived classes must call
   // this function after each attempt at downloading the urls provided
@@ skipping 20 matching lines @@
 
   std::vector<DownloadMetrics> download_metrics_;
 
   DISALLOW_COPY_AND_ASSIGN(CrxDownloader);
 };
 
 }  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_CRX_DOWNLOADER_H_