Persist download interrupt reason, both target and current paths, and url_chain.

chrome/browser/history/download_database.h

Index: chrome/browser/history/download_database.h
diff --git a/chrome/browser/history/download_database.h b/chrome/browser/history/download_database.h
index 8cf07ab44b1c5a4b575f193eac84c7e8a93d0389..80cc59e6556d4d49d2f914224bd38dceae3a6adb 100644
--- a/chrome/browser/history/download_database.h
+++ b/chrome/browser/history/download_database.h
@@ -69,6 +69,10 @@ class DownloadDatabase {
   // database. See http://crbug.com/140687
   bool MigrateDownloadsState();
 
+  // Returns true if able to successfully add the last interrupt reason and the
+  // two target paths to downloads.
+  bool MigrateDownloadsReasonPathsAndDangerType();
+
   // Creates the downloads table if needed.
   bool InitDownloadTable();
 
@@ -77,6 +81,13 @@ class DownloadDatabase {
   bool DropDownloadTable();
 
  private:
+  // Reason for dropping a particular record.
+  enum DroppedReason {
+    DROPPED_REASON_BAD_STATE = 0,
+    DROPPED_REASON_BAD_DANGER_TYPE = 1,
+    DROPPED_REASON_MAX
+  };
+
   bool EnsureColumnExists(const std::string& name, const std::string& type);
 
   bool owning_thread_set_;