After fixing more than 50 errors trying to build the theme with Chromium Theme Creator v3 I finally made this theme work in the latest version of chromium.
But there's just one little problem:

It looks like the buttons(back, forward, reload, home, favorite) are hiding under the buttons bar.
I can solve the problem by shrinking the buttons but I doesn't look that good.

Welcome to ChromePlugins


what is the format of the theme ?

It's a chrome.dll.

I guess in addition to the work to hack the chrome.dll, many theme creators are not interested in creating new themes using chrome.dll despite the fact that buttons and almost everything can be skinned and the size of the file exceeds 15Mb

however if Chrome does goes Gold, maybe I would consider creating a theme in chrome.dll

Well you can't change the buttons shapes in a crx theme. That's why I created it in chrome.dll