Google Chrome Extensions is Still in Development
Google Chrome is developing extensions to complement the default features of Google Chrome that still lacking to fulfill the various needs of surf. Extensions is a system which is also used by Firefox, because the extensions system is very easy for the developers to contribute to the Google Chrome development.
But unfortunately, Google Chrome extensions are still under development. So, we can not use it for now. The developers are allowed to contribute, they can upload their own extensions and after the official release of this feature, then the extensions can be used by Google Chrome users.
Let us wait for the release date.
Upload your creations to https://chrome.google.com/extensions