Restores the blue colors from Chrome 50 (reverts https://crbug.com/594076).
In Chrome 51, Chrome's Classic Theme turned gray on Windows and Linux.
This theme brings back the blue colors from Chrome 50.
Unlike the other "Classic blue theme" extension in the Chrome Web Store, this extension does not change any other style, so you will get the modern classic theme - i.e. Chrome 50's Classic Theme.
Update (version 2): Use a subtle gradient instead of a single color to look identical to the default theme of Chrome 50 on Linux/Windows. Now the theme also works on macOS.