[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 622 matching lines @@
   int64 next_tracker_id_;
   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());

[nhiroki, 2014/09/03 04:30:06]

This init->drop-init sequence might not make sense when using
|in_memory_env_|...?

[peria, 2014/09/03 09:24:21]

It works well as long as we use |in_memory_env_|.

ref. 
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/leveld...
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/leveld...

[nhiroki, 2014/09/03 09:52:20]

I see. I wrongly assumed |in_memory_env_| is recreated in the sequence. Thanks
for your explanation.

+
+  DropDatabase();
+  scoped_ptr<LevelDBWrapper> db = InitializeLevelDB();
+  db->Put(kServiceMetadataKey, "Unparsable string");
+  db->Commit();
+  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