add a download slices table into history download db

components/history/core/browser/download_database.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 COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include <map>
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/threading/platform_thread.h"
 #include "components/history/core/browser/download_types.h"
 
 namespace sql {
 class Connection;
 }
 
 namespace history {
 
+struct DownloadJobInfo;
 struct DownloadRow;
 
 // Maintains a table of downloads.
 class DownloadDatabase {
  public:
   // Must call InitDownloadTable before using any other functions.
   DownloadDatabase(DownloadInterruptReason download_interrupt_reason_none,
                    DownloadInterruptReason download_interrupt_reason_crash);
   virtual ~DownloadDatabase();
 
@@ skipping 71 matching lines @@
   // state are not updated during browser shutdown (particularly when crashing).
   // On the next start such entries are considered interrupted with
   // interrupt reason |DOWNLOAD_INTERRUPT_REASON_CRASH|.  This function
   // fixes such entries.
   void EnsureInProgressEntriesCleanedUp();
 
   bool EnsureColumnExists(const std::string& name, const std::string& type);
 
   void RemoveDownloadURLs(uint32_t id);
 
+  // Creates a new download job if it doesn't exist, or updates an existing one.
+  // Returns true on success, or false otherwise.
+  bool CreateOrUpdateDownloadJob(const DownloadJobInfo& info);
+
+  // Delete all the download jobs associated with one DownloadRow.
+  void RemoveDownloadJobs(DownloadId id);
+
+  // Helper method to query the download jobs for all the records in
+  // |download_row_map|.
+  void QueryDownloadJobs(std::map<uint32_t, DownloadRow*>* download_row_map);

[Scott Hess - ex-Googler, 2017/02/08 22:01:39]

I still want this key to be a DownloadId, but I can see that the overall file
isn't consistent in use of DownloadId versus uint32_t, so I'll just encourage a
someday-if-you-have-time cleanup.

[qinmin, 2017/02/09 01:01:42]

Done. Changed all member functions that using uint32_t to DownloadId

+
   bool owning_thread_set_;
   base::PlatformThreadId owning_thread_;
 
   // Initialized to false on construction, and checked in all functional
   // routines post-migration in the database for a possible call to
   // CleanUpInProgressEntries().  This allows us to avoid
   // doing the cleanup until after any DB migration and unless we are
   // actually use the downloads database.
   bool in_progress_entry_cleanup_completed_;
 
   // Those constants are defined in the embedder and injected into the
   // database in the constructor. They represent the interrupt reason
   // to use for respectively an undefined value and in case of a crash.
   DownloadInterruptReason download_interrupt_reason_none_;
   DownloadInterruptReason download_interrupt_reason_crash_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadDatabase);
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_DOWNLOAD_DATABASE_H_