It would be nice to have a native file sync client for ChromeOS devices. Google has an API in place that would allow for a SeaDrive-like client that would have the same style of integration with the system as Google Drive. See this topic on the Chrome Developer site: chrome.fileSystemProvider
As a workaround I use an android file manager (i.e.Total Commander) to acces my seafile server via webdav. But native Chrome OS support would be nice.