[Retry][SyncFS] Implement LargestKnownChangeID handling

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/message_loop/message_loop_proxy.h"
@@ skipping 383 matching lines @@
     details->set_change_id(++current_change_id_);
   }
 
   void ApplyContentChangeToMetadata(FileMetadata* file) {
     FileDetails* details = file->mutable_details();
     details->set_md5(
         "md5_value_" + base::Int64ToString(next_md5_sequence_number_++));
     details->set_change_id(++current_change_id_);
   }
 
+  void ApplyNoopChangeToMetadata(FileMetadata* file) {
+    file->mutable_details()->set_change_id(++current_change_id_);
+  }
+
   void PushToChangeList(scoped_ptr<google_apis::ChangeResource> change,
                         ScopedVector<google_apis::ChangeResource>* changes) {
     changes->push_back(change.release());
   }
 
   leveldb::Status PutFileToDB(leveldb::DB* db, const FileMetadata& file) {
     std::string key = "FILE: " + file.file_id();
     std::string value;
     file.SerializeToString(&value);
     return db->Put(leveldb::WriteOptions(), key, value);
@@ skipping 327 matching lines @@
     &new_file,
   };
 
   SetUpDatabaseByTrackedFiles(tracked_files, arraysize(tracked_files));
   EXPECT_EQ(SYNC_STATUS_OK, InitializeMetadataDatabase());
 
   ApplyRenameChangeToMetadata("renamed", &renamed_file.metadata);
   ApplyReorganizeChangeToMetadata(folder.metadata.file_id(),
                                   &reorganized_file.metadata);
   ApplyContentChangeToMetadata(&updated_file.metadata);
+  ApplyNoopChangeToMetadata(&noop_file.metadata);

[kinuko, 2013/11/18 06:57:11]

Care to add a comment why we need it?

[tzik, 2013/11/18 07:17:13]

Done.

 
   ScopedVector<google_apis::ChangeResource> changes;
   PushToChangeList(
       CreateChangeResourceFromMetadata(renamed_file.metadata), &changes);
   PushToChangeList(
       CreateChangeResourceFromMetadata(reorganized_file.metadata), &changes);
   PushToChangeList(
       CreateChangeResourceFromMetadata(updated_file.metadata), &changes);
   PushToChangeList(
       CreateChangeResourceFromMetadata(noop_file.metadata), &changes);
@@ skipping 238 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