[SyncFS] Retry initialization of MetadataDatabase on failure of loading ServiceMetadata

chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc

 // Copyright 2013 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 "chrome/browser/sync_file_system/drive_backend/metadata_database.h"
 
 #include "base/bind.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 623 matching lines @@
   int64 next_file_id_number_;
   int64 next_md5_sequence_number_;
 
   DISALLOW_COPY_AND_ASSIGN(MetadataDatabaseTest);
 };
 
 TEST_F(MetadataDatabaseTest, InitializationTest_Empty) {
   EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
   DropDatabase();
   EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
+
+  DropDatabase();
+
+  scoped_ptr<LevelDBWrapper> db = InitializeLevelDB();
+  db->Put(kServiceMetadataKey, "Unparsable string");
+  EXPECT_TRUE(db->Commit().ok());
+  db.reset();
+
+  EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
 }
 
 TEST_F(MetadataDatabaseTest, InitializationTest_SimpleTree) {
   TrackedFile sync_root(CreateTrackedSyncRoot());
   TrackedFile app_root(CreateTrackedFolder(sync_root, "app_id"));
   app_root.tracker.set_app_id(app_root.metadata.details().title());
   app_root.tracker.set_tracker_kind(TRACKER_KIND_APP_ROOT);
 
   TrackedFile file(CreateTrackedFile(app_root, "file"));
   TrackedFile folder(CreateTrackedFolder(app_root, "folder"));
@@ skipping 504 matching lines @@
   EXPECT_TRUE(file->HasKey("details"));
 
   ASSERT_TRUE(files->GetDictionary(1, &file));
   EXPECT_TRUE(file->GetString("title", &str) && str == "file_0");
   EXPECT_TRUE(file->GetString("type", &str) && str == "file");
   EXPECT_TRUE(file->HasKey("details"));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system