Sync: Remove several unused columns from Sync DB meta_info table

BUG=118356,124140

Review URL: https://codereview.chromium.org/1509673005

Cr-Commit-Position: refs/heads/master@{#364218}

4 files changed, 234 insertions, 91 deletions

diff --git a/sync/syncable/directory_backing_store.cc b/sync/syncable/directory_backing_store.cc
index cbe943b..e57f246 100644
--- a/sync/syncable/directory_backing_store.cc
+++ b/sync/syncable/directory_backing_store.cc
@@ -34,7 +34,7 @@ namespace syncer {
 namespace syncable {
 
 // Increment this version whenever updating DB tables.
-const int32 kCurrentDBVersion = 89;
+const int32 kCurrentDBVersion = 90;
 
 // Iterate over the fields of |entry| and bind each to |statement| for
 // updating.  Returns the number of args bound.
@@ -257,7 +257,8 @@ void UploadModelTypeEntryCount(const int total_specifics_copies,
 DirectoryBackingStore::DirectoryBackingStore(const string& dir_name)
     : dir_name_(dir_name),
       database_page_size_(32768),
-      needs_column_refresh_(false) {
+      needs_metas_column_refresh_(false),
+      needs_share_info_column_refresh_(false) {
   DCHECK(base::ThreadTaskRunnerHandle::IsSet());
   ResetAndCreateConnection();
 }
@@ -267,7 +268,8 @@ DirectoryBackingStore::DirectoryBackingStore(const string& dir_name,
     : dir_name_(dir_name),
       database_page_size_(32768),
       db_(db),
-      needs_column_refresh_(false) {
+      needs_metas_column_refresh_(false),
+      needs_share_info_column_refresh_(false) {
   DCHECK(base::ThreadTaskRunnerHandle::IsSet());
 }
 
@@ -552,10 +554,16 @@ bool DirectoryBackingStore::InitializeTables() {
       version_on_disk = 89;
   }
 
+  // Version 90 migration removes several columns from share_info table.
+  if (version_on_disk == 89) {
+    if (MigrateVersion89To90())
+      version_on_disk = 90;
+  }
+
   // If one of the migrations requested it, drop columns that aren't current.
   // It's only safe to do this after migrating all the way to the current
   // version.
-  if (version_on_disk == kCurrentDBVersion && needs_column_refresh_) {
+  if (version_on_disk == kCurrentDBVersion && needs_column_refresh()) {
     if (!RefreshColumns())
       version_on_disk = 0;
   }
@@ -573,15 +581,6 @@ bool DirectoryBackingStore::InitializeTables() {
       return false;
   }
 
-  sql::Statement s(db_->GetUniqueStatement(
-          "SELECT db_create_version, db_create_time FROM share_info"));
-  if (!s.Step())
-    return false;
-  string db_create_version = s.ColumnString(0);
-  int db_create_time = s.ColumnInt(1);
-  DVLOG(1) << "DB created at " << db_create_time << " by version " <<
-      db_create_version;
-
   return transaction.Commit();
 }
 
@@ -589,55 +588,58 @@ bool DirectoryBackingStore::InitializeTables() {
 // the currently used columns then copying all rows from the old tables into
 // this new one.  The tables are then rearranged so the new replaces the old.
 bool DirectoryBackingStore::RefreshColumns() {
-  DCHECK(needs_column_refresh_);
+  DCHECK(needs_metas_column_refresh_ || needs_share_info_column_refresh_);
 
-  // Create a new table named temp_metas.
-  SafeDropTable("temp_metas");
-  if (!CreateMetasTable(true))
-    return false;
+  if (needs_metas_column_refresh_) {
+    // Create a new table named temp_metas.
+    SafeDropTable("temp_metas");
+    if (!CreateMetasTable(true))
+      return false;
 
-  // Populate temp_metas from metas.
-  //
-  // At this point, the metas table may contain columns belonging to obsolete
-  // schema versions.  This statement explicitly lists only the columns that
-  // belong to the current schema version, so the obsolete columns will be
-  // effectively dropped once we rename temp_metas over top of metas.
-  std::string query = "INSERT INTO temp_metas (";
-  AppendColumnList(&query);
-  query.append(") SELECT ");
-  AppendColumnList(&query);
-  query.append(" FROM metas");
-  if (!db_->Execute(query.c_str()))
-    return false;
+    // Populate temp_metas from metas.
+    //
+    // At this point, the metas table may contain columns belonging to obsolete
+    // schema versions.  This statement explicitly lists only the columns that
+    // belong to the current schema version, so the obsolete columns will be
+    // effectively dropped once we rename temp_metas over top of metas.
+    std::string query = "INSERT INTO temp_metas (";
+    AppendColumnList(&query);
+    query.append(") SELECT ");
+    AppendColumnList(&query);
+    query.append(" FROM metas");
+    if (!db_->Execute(query.c_str()))
+      return false;
 
-  // Drop metas.
-  SafeDropTable("metas");
+    // Drop metas.
+    SafeDropTable("metas");
 
-  // Rename temp_metas -> metas.
-  if (!db_->Execute("ALTER TABLE temp_metas RENAME TO metas"))
-    return false;
+    // Rename temp_metas -> metas.
+    if (!db_->Execute("ALTER TABLE temp_metas RENAME TO metas"))
+      return false;
 
-  // Repeat the process for share_info.
-  SafeDropTable("temp_share_info");
-  if (!CreateShareInfoTable(true))
-    return false;
+    needs_metas_column_refresh_ = false;
+  }
 
-  // TODO(rlarocque, 124140): Remove notification_state.
-  if (!db_->Execute(
-          "INSERT INTO temp_share_info (id, name, store_birthday, "
-          "db_create_version, db_create_time, next_id, cache_guid,"
-          "notification_state, bag_of_chips) "
-          "SELECT id, name, store_birthday, db_create_version, "
-          "db_create_time, next_id, cache_guid, notification_state, "
-          "bag_of_chips "
-          "FROM share_info"))
-    return false;
+  if (needs_share_info_column_refresh_) {
+    // Repeat the process for share_info.
+    SafeDropTable("temp_share_info");
+    if (!CreateShareInfoTable(true))
+      return false;
 
-  SafeDropTable("share_info");
-  if (!db_->Execute("ALTER TABLE temp_share_info RENAME TO share_info"))
-    return false;
+    if (!db_->Execute(
+            "INSERT INTO temp_share_info (id, name, store_birthday, "
+            "cache_guid, bag_of_chips) "
+            "SELECT id, name, store_birthday, cache_guid, bag_of_chips "
+            "FROM share_info"))
+      return false;
+
+    SafeDropTable("share_info");
+    if (!db_->Execute("ALTER TABLE temp_share_info RENAME TO share_info"))
+      return false;
+
+    needs_share_info_column_refresh_ = false;
+  }
 
-  needs_column_refresh_ = false;
   return true;
 }
 
@@ -776,7 +778,8 @@ void DirectoryBackingStore::DropAllTables() {
   SafeDropTable("extended_attributes");
   SafeDropTable("models");
   SafeDropTable("temp_models");
-  needs_column_refresh_ = false;
+  needs_metas_column_refresh_ = false;
+  needs_share_info_column_refresh_ = false;
 }
 
 // static
@@ -864,7 +867,7 @@ bool DirectoryBackingStore::MigrateVersion67To68() {
   //   string SERVER_NAME
   // No data migration is necessary, but we should do a column refresh.
   SetVersion(68);
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
   return true;
 }
 
@@ -877,7 +880,7 @@ bool DirectoryBackingStore::MigrateVersion69To70() {
   if (!db_->Execute(
           "ALTER TABLE metas ADD COLUMN unique_client_tag varchar"))
     return false;
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
 
   if (!db_->Execute(
           "UPDATE metas SET unique_server_tag = singleton_tag"))
@@ -958,7 +961,7 @@ bool DirectoryBackingStore::MigrateVersion68To69() {
     return false;
 
   SetVersion(69);
-  needs_column_refresh_ = true;  // Trigger deletion of old columns.
+  needs_metas_column_refresh_ = true;  // Trigger deletion of old columns.
   return true;
 }
 
@@ -1138,7 +1141,7 @@ bool DirectoryBackingStore::MigrateVersion75To76() {
   //   autofill_profiles_added_during_migration
   // No data migration is necessary, but we should do a column refresh.
   SetVersion(76);
-  needs_column_refresh_ = true;
+  needs_share_info_column_refresh_ = true;
   return true;
 }
 
@@ -1232,7 +1235,7 @@ bool DirectoryBackingStore::MigrateVersion80To81() {
   }
 
   SetVersion(81);
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
   return true;
 }
 
@@ -1410,7 +1413,7 @@ bool DirectoryBackingStore::MigrateVersion85To86() {
   }
 
   SetVersion(86);
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
   return true;
 }
 
@@ -1422,7 +1425,7 @@ bool DirectoryBackingStore::MigrateVersion86To87() {
     return false;
   }
   SetVersion(87);
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
   return true;
 }
 
@@ -1443,7 +1446,19 @@ bool DirectoryBackingStore::MigrateVersion88To89() {
     return false;
   }
   SetVersion(89);
-  needs_column_refresh_ = true;
+  needs_metas_column_refresh_ = true;
+  return true;
+}
+
+bool DirectoryBackingStore::MigrateVersion89To90() {
+  // This change removed 4 columns from meta_info:
+  //   db_create_version
+  //   db_create_time
+  //   next_id
+  //   notification_state
+  // No data migration is necessary, but we should do a column refresh.
+  SetVersion(90);
+  needs_share_info_column_refresh_ = true;
   return true;
 }
 
@@ -1477,24 +1492,13 @@ bool DirectoryBackingStore::CreateTables() {
             "(?, "  // id
             "?, "   // name
             "?, "   // store_birthday
-            "?, "   // db_create_version
-            "?, "   // db_create_time
-            "-2, "  // next_id
             "?, "   // cache_guid
-            // TODO(rlarocque, 124140): Remove notification_state field.
-            "?, "   // notification_state
             "?);"));  // bag_of_chips
     s.BindString(0, dir_name_);                   // id
     s.BindString(1, dir_name_);                   // name
     s.BindString(2, std::string());               // store_birthday
-    // TODO(akalin): Remove this unused db_create_version field. (Or
-    // actually use it for something.) http://crbug.com/118356
-    s.BindString(3, "Unknown");                   // db_create_version
-    s.BindInt(4, static_cast<int32>(time(0)));    // db_create_time
-    s.BindString(5, GenerateCacheGUID());         // cache_guid
-    // TODO(rlarocque, 124140): Remove this unused notification-state field.
-    s.BindBlob(6, NULL, 0);                       // notification_state
-    s.BindBlob(7, NULL, 0);                       // bag_of_chips
+    s.BindString(3, GenerateCacheGUID());         // cache_guid
+    s.BindBlob(4, NULL, 0);                       // bag_of_chips
     if (!s.Run())
       return false;
   }
@@ -1600,12 +1604,7 @@ bool DirectoryBackingStore::CreateShareInfoTable(bool is_temporary) {
       "id TEXT primary key, "
       "name TEXT, "
       "store_birthday TEXT, "
-      "db_create_version TEXT, "
-      "db_create_time INT, "
-      "next_id INT default -2, "
       "cache_guid TEXT, "
-      // TODO(rlarocque, 124140): Remove notification_state field.
-      "notification_state BLOB, "
       "bag_of_chips BLOB"
       ")");
   return db_->Execute(query.c_str());
@@ -1721,7 +1720,7 @@ bool DirectoryBackingStore::Vacuum() {
 }
 
 bool DirectoryBackingStore::needs_column_refresh() const {
-  return needs_column_refresh_;
+  return needs_metas_column_refresh_ || needs_share_info_column_refresh_;
 }
 
 void DirectoryBackingStore::ResetAndCreateConnection() {
diff --git a/sync/syncable/directory_backing_store.h b/sync/syncable/directory_backing_store.h
index 422d13d..e3c8598 100644
--- a/sync/syncable/directory_backing_store.h
+++ b/sync/syncable/directory_backing_store.h
@@ -173,6 +173,7 @@ class SYNC_EXPORT_PRIVATE DirectoryBackingStore : public base::NonThreadSafe {
   bool MigrateVersion86To87();
   bool MigrateVersion87To88();
   bool MigrateVersion88To89();
+  bool MigrateVersion89To90();
 
   // Accessor for needs_column_refresh_.  Used in tests.
   bool needs_column_refresh() const;
@@ -249,7 +250,8 @@ class SYNC_EXPORT_PRIVATE DirectoryBackingStore : public base::NonThreadSafe {
 
   // Set to true if migration left some old columns around that need to be
   // discarded.
-  bool needs_column_refresh_;
+  bool needs_metas_column_refresh_;
+  bool needs_share_info_column_refresh_;
 
   // We keep a copy of the Closure so we reinstall it when the underlying
   // sql::Connection is destroyed/recreated.
diff --git a/sync/syncable/directory_backing_store_unittest.cc b/sync/syncable/directory_backing_store_unittest.cc
index 24a2014..56e91b0 100644
--- a/sync/syncable/directory_backing_store_unittest.cc
+++ b/sync/syncable/directory_backing_store_unittest.cc
@@ -100,9 +100,10 @@ class MigrationTest : public testing::TestWithParam<int> {
   void SetUpVersion87Database(sql::Connection* connection);
   void SetUpVersion88Database(sql::Connection* connection);
   void SetUpVersion89Database(sql::Connection* connection);
+  void SetUpVersion90Database(sql::Connection* connection);
 
   void SetUpCurrentDatabaseAndCheckVersion(sql::Connection* connection) {
-    SetUpVersion89Database(connection);  // Prepopulates data.
+    SetUpVersion90Database(connection);  // Prepopulates data.
     scoped_ptr<TestDirectoryBackingStore> dbs(
         new TestDirectoryBackingStore(GetUsername(), connection));
     ASSERT_EQ(kCurrentDBVersion, dbs->GetVersion());
@@ -2791,7 +2792,6 @@ void MigrationTest::SetUpVersion88Database(sql::Connection* connection) {
   ASSERT_TRUE(connection->CommitTransaction());
 }
 
-
 void MigrationTest::SetUpVersion89Database(sql::Connection* connection) {
   ASSERT_TRUE(connection->is_open());
   ASSERT_TRUE(connection->BeginTransaction());
@@ -2905,6 +2905,117 @@ void MigrationTest::SetUpVersion89Database(sql::Connection* connection) {
   ASSERT_TRUE(connection->CommitTransaction());
 }
 
+void MigrationTest::SetUpVersion90Database(sql::Connection* connection) {
+  ASSERT_TRUE(connection->is_open());
+  ASSERT_TRUE(connection->BeginTransaction());
+  ASSERT_TRUE(connection->Execute(
+      "CREATE TABLE share_version (id VARCHAR(128) primary key, data INT);"
+      "INSERT INTO 'share_version' VALUES('nick@chromium.org',90);"
+      "CREATE TABLE models (model_id BLOB primary key, progress_marker BLOB, tr"
+         "ansaction_version BIGINT default 0, context BLOB);"
+      "INSERT INTO 'models' VALUES(X'C2881000',X'0888810218B605',1,NULL);"
+      "CREATE TABLE 'metas'(metahandle bigint primary key ON CONFLICT FAIL,base"
+         "_version bigint default -1,server_version bigint default 0,local_exte"
+         "rnal_id bigint default 0,transaction_version bigint default 0,mtime b"
+         "igint default 0,server_mtime bigint default 0,ctime bigint default 0,"
+         "server_ctime bigint default 0,id varchar(255) default 'r',parent_id v"
+         "archar(255) default 'r',server_parent_id varchar(255) default 'r',is_"
+         "unsynced bit default 0,is_unapplied_update bit default 0,is_del bit d"
+         "efault 0,is_dir bit default 0,server_is_dir bit default 0,server_is_d"
+         "el bit default 0,non_unique_name varchar,server_non_unique_name varch"
+         "ar(255),unique_server_tag varchar,unique_client_tag varchar,unique_bo"
+         "okmark_tag varchar,specifics blob,server_specifics blob,base_server_s"
+         "pecifics blob,server_unique_position blob,unique_position blob,attach"
+         "ment_metadata blob,server_attachment_metadata blob);"
+      "INSERT INTO 'metas' VALUES(1,-1,0,0,0,"
+         META_PROTO_TIMES_VALS(1)
+         ",'r','r','r',0,0,0,1,0,0,NULL,NULL,NULL,NULL,X'',X'',X'',NULL,X'2200'"
+         ",X'2200',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(6,694,694,6,0,"
+         META_PROTO_TIMES_VALS(6)
+         ",'s_ID_6','s_ID_9','s_ID_9',0,0,0,1,1,0,'The Internet','The Internet'"
+         ",NULL,NULL,X'6754307476346749735A5734654D653273625336557753582F77673D"
+         "',X'C2881000',X'C2881000',NULL,X'22247FFFFFFFFFC000006754307476346749"
+         "735A5734654D653273625336557753582F77673D',X'22247FFFFFFFFFC0000067543"
+         "07476346749735A5734654D653273625336557753582F77673D',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(7,663,663,0,0,"
+         META_PROTO_TIMES_VALS(7)
+         ",'s_ID_7','r','r',0,0,0,1,1,0,'Google Chrome','Google Chrome','google"
+         "_chrome',NULL,X'',NULL,NULL,NULL,X'2200',X'2200',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(8,664,664,0,0,"
+         META_PROTO_TIMES_VALS(8)
+         ",'s_ID_8','s_ID_7','s_ID_7',0,0,0,1,1,0,'Bookmarks','Bookmarks','goog"
+         "le_chrome_bookmarks',NULL,X'',X'C2881000',X'C2881000',NULL,X'2200',X'"
+         "2200',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(9,665,665,1,0,"
+         META_PROTO_TIMES_VALS(9)
+         ",'s_ID_9','s_ID_8','s_ID_8',0,0,0,1,1,0,'Bookmark Bar','Bookmark Bar'"
+         ",'bookmark_bar',NULL,X'',X'C2881000',X'C2881000',NULL,X'2200',X'2200'"
+         ",NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(10,666,666,2,0,"
+         META_PROTO_TIMES_VALS(10)
+         ",'s_ID_10','s_ID_8','s_ID_8',0,0,0,1,1,0,'Other Bookmarks','Other Boo"
+         "kmarks','other_bookmarks',NULL,X'',X'C2881000',X'C2881000',NULL,X'220"
+         "0',X'2200',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(11,683,683,8,0,"
+         META_PROTO_TIMES_VALS(11)
+         ",'s_ID_11','s_ID_6','s_ID_6',0,0,0,0,0,0,'Home (The Chromium Projects"
+         ")','Home (The Chromium Projects)',NULL,NULL,X'50514C784A456D623579366"
+         "267644237646A7A2B62314130346E493D',X'C28810220A18687474703A2F2F646576"
+         "2E6368726F6D69756D2E6F72672F1206414741545741',X'C28810290A1D687474703"
+         "A2F2F6465762E6368726F6D69756D2E6F72672F6F7468657212084146414756415346"
+         "',NULL,X'22247FFFFFFFFFF0000050514C784A456D623579366267644237646A7A2B"
+         "62314130346E493D',X'22247FFFFFFFFFF0000050514C784A456D623579366267644"
+         "237646A7A2B62314130346E493D',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(12,685,685,9,0,"
+         META_PROTO_TIMES_VALS(12)
+         ",'s_ID_12','s_ID_6','s_ID_6',0,0,0,1,1,0,'Extra Bookmarks','Extra Boo"
+         "kmarks',NULL,NULL,X'7867626A704A646134635A6F616C376A49513338734B46324"
+         "837773D',X'C2881000',X'C2881000',NULL,X'222480000000000000007867626A7"
+         "04A646134635A6F616C376A49513338734B46324837773D',X'222480000000000000"
+         "007867626A704A646134635A6F616C376A49513338734B46324837773D',NULL,NULL"
+         ");"
+      "INSERT INTO 'metas' VALUES(13,687,687,10,0,"
+         META_PROTO_TIMES_VALS(13)
+         ",'s_ID_13','s_ID_6','s_ID_6',0,0,0,0,0,0,'ICANN | Internet Corporatio"
+         "n for Assigned Names and Numbers','ICANN | Internet Corporation for A"
+         "ssigned Names and Numbers',NULL,NULL,X'3142756B572F774176695650417967"
+         "2B304A614A514B3452384A413D',X'C28810240A15687474703A2F2F7777772E69636"
+         "16E6E2E636F6D2F120B504E474158463041414646',X'C28810200A15687474703A2F"
+         "2F7777772E6963616E6E2E636F6D2F120744414146415346',NULL,X'22247FFFFFFF"
+         "FFF200003142756B572F7741766956504179672B304A614A514B3452384A413D',X'2"
+         "2247FFFFFFFFFF200003142756B572F7741766956504179672B304A614A514B345238"
+         "4A413D',NULL,NULL);"
+      "INSERT INTO 'metas' VALUES(14,692,692,11,0,"
+         META_PROTO_TIMES_VALS(14)
+         ",'s_ID_14','s_ID_6','s_ID_6',0,0,0,0,0,0,'The WebKit Open Source Proj"
+         "ect','The WebKit Open Source Project',NULL,NULL,X'5A5678314E797636457"
+         "9524D3177494F7236563159552F6E644C553D',X'C288101A0A12687474703A2F2F77"
+         "65626B69742E6F72672F1204504E4758',X'C288101C0A13687474703A2F2F7765626"
+         "B69742E6F72672F781205504E473259',NULL,X'222480000000001000005A5678314"
+         "E7976364579524D3177494F7236563159552F6E644C553D',X'222480000000001000"
+         "005A5678314E7976364579524D3177494F7236563159552F6E644C553D',NULL,NULL"
+         ");"
+      "CREATE TABLE deleted_metas (metahandle bigint primary key ON CONFLICT FA"
+         "IL,base_version bigint default -1,server_version bigint default 0,loc"
+         "al_external_id bigint default 0,transaction_version bigint default 0,"
+         "mtime bigint default 0,server_mtime bigint default 0,ctime bigint def"
+         "ault 0,server_ctime bigint default 0,id varchar(255) default 'r',pare"
+         "nt_id varchar(255) default 'r',server_parent_id varchar(255) default "
+         "'r',is_unsynced bit default 0,is_unapplied_update bit default 0,is_de"
+         "l bit default 0,is_dir bit default 0,server_is_dir bit default 0,serv"
+         "er_is_del bit default 0,non_unique_name varchar,server_non_unique_nam"
+         "e varchar(255),unique_server_tag varchar,unique_client_tag varchar,un"
+         "ique_bookmark_tag varchar,specifics blob,server_specifics blob,base_s"
+         "erver_specifics blob,server_unique_position blob,unique_position blob"
+         ",attachment_metadata blob,server_attachment_metadata blob);"
+      "CREATE TABLE 'share_info' (id TEXT primary key, name TEXT, store_birthda"
+         "y TEXT, cache_guid TEXT, bag_of_chips BLOB);"
+      "INSERT INTO 'share_info' VALUES('nick@chromium.org','nick@chromium.org',"
+         "'c27e9f59-08ca-46f8-b0cc-f16a2ed778bb','9010788312004066376x-66092343"
+         "93368420856x',NULL);"));
+  ASSERT_TRUE(connection->CommitTransaction());
+}
 
 TEST_F(DirectoryBackingStoreTest, MigrateVersion67To68) {
   sql::Connection connection;
@@ -3396,6 +3507,30 @@ TEST_F(DirectoryBackingStoreTest, MigrateVersion88To89) {
   EXPECT_TRUE(dbs->needs_column_refresh());
 }
 
+TEST_F(DirectoryBackingStoreTest, MigrateVersion89To90) {
+  sql::Connection connection;
+  ASSERT_TRUE(connection.OpenInMemory());
+  SetUpVersion89Database(&connection);
+  ASSERT_TRUE(connection.DoesColumnExist("share_info", "db_create_version"));
+  ASSERT_TRUE(connection.DoesColumnExist("share_info", "db_create_time"));
+  ASSERT_TRUE(connection.DoesColumnExist("share_info", "next_id"));
+  ASSERT_TRUE(connection.DoesColumnExist("share_info", "notification_state"));
+
+  scoped_ptr<TestDirectoryBackingStore> dbs(
+      new TestDirectoryBackingStore(GetUsername(), &connection));
+  ASSERT_TRUE(dbs->MigrateVersion89To90());
+  ASSERT_EQ(90, dbs->GetVersion());
+  EXPECT_TRUE(dbs->needs_column_refresh());
+
+  ASSERT_TRUE(dbs->RefreshColumns());
+  EXPECT_FALSE(dbs->needs_column_refresh());
+
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "db_create_version"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "db_create_time"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "next_id"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "notification_state"));
+}
+
 // The purpose of this test case is to make it easier to get a dump of the
 // database so you can implement a SetUpVersionYDatabase method.  Here's what
 // you should do:
@@ -3417,13 +3552,13 @@ TEST_F(DirectoryBackingStoreTest, MigrateToLatestAndDump) {
   {
     sql::Connection connection;
     ASSERT_TRUE(connection.Open(GetDatabasePath()));
-    SetUpVersion88Database(&connection);  // Update this.
+    SetUpVersion89Database(&connection);  // Update this.
 
     scoped_ptr<TestDirectoryBackingStore> dbs(
         new TestDirectoryBackingStore(GetUsername(), &connection));
-    ASSERT_TRUE(dbs->MigrateVersion88To89());  // Update this.
+    ASSERT_TRUE(dbs->MigrateVersion89To90());  // Update this.
     ASSERT_TRUE(LoadAndIgnoreReturnedData(dbs.get()));
-    EXPECT_EQ(89, dbs->GetVersion());  // Update this.
+    EXPECT_EQ(90, dbs->GetVersion());  // Update this.
     ASSERT_FALSE(dbs->needs_column_refresh());
   }
   // Set breakpoint here.
@@ -3530,6 +3665,9 @@ TEST_P(MigrationTest, ToCurrentVersion) {
     case 89:
       SetUpVersion89Database(&connection);
       break;
+    case 90:
+      SetUpVersion90Database(&connection);
+      break;
     default:
       // If you see this error, it may mean that you've increased the
       // database version number but you haven't finished adding unit tests
@@ -3581,9 +3719,6 @@ TEST_P(MigrationTest, ToCurrentVersion) {
   // Removed extended attributes in Version 72.
   ASSERT_FALSE(connection.DoesTableExist("extended_attributes"));
 
-  // Columns added in Version 73.
-  ASSERT_TRUE(connection.DoesColumnExist("share_info", "notification_state"));
-
   // Column replaced in version 75.
   ASSERT_TRUE(connection.DoesColumnExist("models", "progress_marker"));
   ASSERT_FALSE(connection.DoesColumnExist("models", "last_download_timestamp"));
@@ -3630,6 +3765,12 @@ TEST_P(MigrationTest, ToCurrentVersion) {
   ASSERT_TRUE(
       connection.DoesColumnExist("metas", "server_attachment_metadata"));
 
+  // Columns removed in version 90.
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "db_create_version"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "db_create_time"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "next_id"));
+  ASSERT_FALSE(connection.DoesColumnExist("share_info", "notification_state"));
+
   // Check download_progress state (v75 migration)
   ASSERT_EQ(694,
       dir_info.kernel_info.download_progress[BOOKMARKS]
diff --git a/sync/test/test_directory_backing_store.h b/sync/test/test_directory_backing_store.h
index 1e71816..53f89e5 100644
--- a/sync/test/test_directory_backing_store.h
+++ b/sync/test/test_directory_backing_store.h
@@ -52,6 +52,7 @@ class TestDirectoryBackingStore : public DirectoryBackingStore {
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion86To87);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion87To88);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion88To89);
+  FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion89To90);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, DetectInvalidPosition);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, ModelTypeIds);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, Corruption);