add a download slices table into history download db

components/history/core/browser/history_database.cc

 // 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.
 
 #include "components/history/core/browser/history_database.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <set>
@@ skipping 18 matching lines @@
 #include "base/mac/mac_util.h"
 #endif
 
 namespace history {
 
 namespace {
 
 // Current version number. We write databases at the "current" version number,
 // but any previous version that can read the "compatible" one can make do with
 // our database without *too* many bad effects.
-const int kCurrentVersionNumber = 32;
+const int kCurrentVersionNumber = 33;
 const int kCompatibleVersionNumber = 16;
 const char kEarlyExpirationThresholdKey[] = "early_expiration_threshold";
 const int kMaxHostsInMemory = 10000;
 
 }  // namespace
 
 HistoryDatabase::HistoryDatabase(
     DownloadInterruptReason download_interrupt_reason_none,
     DownloadInterruptReason download_interrupt_reason_crash)
     : DownloadDatabase(download_interrupt_reason_none,
@@ skipping 479 matching lines @@
 
   if (cur_version == 31) {
     if (!MigrateDownloadSiteInstanceUrl()) {
       LOG(WARNING) << "Unable to migrate history to version 32";
       return sql::INIT_FAILURE;
     }
     cur_version++;
     meta_table_.SetVersionNumber(cur_version);
   }
 
+  if (cur_version == 32) {
+    // New download jobs table is introduced, no migration needed.
+    cur_version++;
+    meta_table_.SetVersionNumber(cur_version);
+  }

[Scott Hess - ex-Googler, 2017/02/06 21:22:16]

maintain the whitespace line between clauses.

[qinmin, 2017/02/06 23:39:22]

Done.

   // When the version is too old, we just try to continue anyway, there should
   // not be a released product that makes a database too old for us to handle.
   LOG_IF(WARNING, cur_version < GetCurrentVersion()) <<
          "History database version " << cur_version << " is too old to handle.";
 
   return sql::INIT_OK;
 }
 
 #if !defined(OS_WIN)
 void HistoryDatabase::MigrateTimeEpoch() {
   // Update all the times in the URLs and visits table in the main database.
   ignore_result(db_.Execute(
       "UPDATE urls "
       "SET last_visit_time = last_visit_time + 11644473600000000 "
       "WHERE id IN (SELECT id FROM urls WHERE last_visit_time > 0);"));
   ignore_result(db_.Execute(
       "UPDATE visits "
       "SET visit_time = visit_time + 11644473600000000 "
       "WHERE id IN (SELECT id FROM visits WHERE visit_time > 0);"));
   ignore_result(db_.Execute(
       "UPDATE segment_usage "
       "SET time_slot = time_slot + 11644473600000000 "
       "WHERE id IN (SELECT id FROM segment_usage WHERE time_slot > 0);"));
 }
 #endif
 
 }  // namespace history