[Downloads] Introduce GUIDs for downloads.

content/browser/download/download_manager_impl.h

 // Copyright (c) 2012 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_MANAGER_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_
 
 #include <stdint.h>
 
 #include <set>
@@ skipping 64 matching lines @@
 
   int RemoveDownloadsByURLAndTime(
       const base::Callback<bool(const GURL&)>& url_filter,
       base::Time remove_begin,
       base::Time remove_end) override;
   int RemoveAllDownloads() override;
   void DownloadUrl(scoped_ptr<DownloadUrlParameters> params) override;
   void AddObserver(Observer* observer) override;
   void RemoveObserver(Observer* observer) override;
   content::DownloadItem* CreateDownloadItem(
+      const std::string& guid,
       uint32_t id,
       const base::FilePath& current_path,
       const base::FilePath& target_path,
       const std::vector<GURL>& url_chain,
       const GURL& referrer_url,
       const std::string& mime_type,
       const std::string& original_mime_type,
       const base::Time& start_time,
       const base::Time& end_time,
       const std::string& etag,
       const std::string& last_modified,
       int64_t received_bytes,
       int64_t total_bytes,
       content::DownloadItem::DownloadState state,
       DownloadDangerType danger_type,
       DownloadInterruptReason interrupt_reason,
       bool opened) override;
   int InProgressCount() const override;
   int NonMaliciousInProgressCount() const override;
   BrowserContext* GetBrowserContext() const override;
   void CheckForHistoryFilesRemoval() override;
   DownloadItem* GetDownload(uint32_t id) override;
+  DownloadItem* GetDownloadByGuid(const std::string& guid) override;
 
   // For testing; specifically, accessed from TestFileErrorInjector.
   void SetDownloadItemFactoryForTesting(
       scoped_ptr<DownloadItemFactory> item_factory);
   void SetDownloadFileFactoryForTesting(
       scoped_ptr<DownloadFileFactory> file_factory);
   virtual DownloadFileFactory* GetDownloadFileFactoryForTesting();
 
   void RemoveUrlDownloader(UrlDownloader* downloader);
 
  private:
   using DownloadSet = std::set<DownloadItem*>;
   using DownloadMap = std::unordered_map<uint32_t, DownloadItemImpl*>;
+  using DownloadGuidMap = std::unordered_map<std::string, DownloadItemImpl*>;
   using DownloadItemImplVector = std::vector<DownloadItemImpl*>;
   using DownloadRemover = base::Callback<bool(const DownloadItemImpl*)>;
 
   // For testing.
   friend class DownloadManagerTest;
   friend class DownloadTest;
 
   void StartDownloadWithId(
       scoped_ptr<DownloadCreateInfo> info,
       scoped_ptr<ByteStreamReader> stream,
@@ skipping 49 matching lines @@
   // Factory for creation of downloads items.
   scoped_ptr<DownloadItemFactory> item_factory_;
 
   // Factory for the creation of download files.
   scoped_ptr<DownloadFileFactory> file_factory_;
 
   // |downloads_| is the owning set for all downloads known to the
   // DownloadManager.  This includes downloads started by the user in
   // this session, downloads initialized from the history system, and
   // "save page as" downloads.
+  // TODO(asanka): Remove this container in favor of downloads_by_guid_ as a
+  // part of http://crbug.com/593020.
   DownloadMap downloads_;
 
+  // Same as the above, but maps from GUID to download item. Note that the
+  // container is case sensitive. Hence the key needs to be normalized to
+  // upper-case when inserting new elements here. Fortunately for us,
+  // DownloadItemImpl already normalizes the string GUID.
+  DownloadGuidMap downloads_by_guid_;
+
   int history_size_;
 
   // True if the download manager has been initialized and requires a shutdown.
   bool shutdown_needed_;
 
   // Observers that want to be notified of changes to the set of downloads.
   base::ObserverList<Observer> observers_;
 
   // The current active browser context.
   BrowserContext* browser_context_;
 
   // Allows an embedder to control behavior. Guaranteed to outlive this object.
   DownloadManagerDelegate* delegate_;
 
   net::NetLog* net_log_;
 
   std::vector<scoped_ptr<UrlDownloader, BrowserThread::DeleteOnIOThread>>
       url_downloaders_;
 
   base::WeakPtrFactory<DownloadManagerImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadManagerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_