Changes to add duration into history database.

chrome/browser/history/history_database.cc

Index: chrome/browser/history/history_database.cc
diff --git a/chrome/browser/history/history_database.cc b/chrome/browser/history/history_database.cc
index 25e8bdadf8be73cd526f843b67077614300bcf79..e48f7cb72ec293db5368a1a2d998728f224e780c 100644
--- a/chrome/browser/history/history_database.cc
+++ b/chrome/browser/history/history_database.cc
@@ -28,7 +28,7 @@ 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
 // or database without *too* many bad effects.
-static const int kCurrentVersionNumber = 20;
+static const int kCurrentVersionNumber = 21;
 static const int kCompatibleVersionNumber = 16;
 static const char kEarlyExpirationThresholdKey[] = "early_expiration_threshold";
 
@@ -307,6 +307,17 @@ sql::InitStatus HistoryDatabase::EnsureCurrentVersion(
     meta_table_.SetValue(kNeedsThumbnailMigrationKey, 1);
   }
 
+  if (cur_version == 20) {
+    // This is the version prior to adding the visit_duration field in visits
+    // database. We need to migrate the database.
+    if (!MigrateVisitsWithoutDuration()) {
+      LOG(WARNING) << "Unable to update history database to version 21.";
+      return sql::INIT_FAILURE;
+    }
+    ++cur_version;
+    meta_table_.SetVersionNumber(cur_version);
+  }
+
   // 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()) <<