WordPress.com for Google Docs Chrome Extension is now allow you to write, read, edit and collaborate within Google Docs to be directly ported over to WordPress.com by retaining most of the formatting along with images. By the use of collaborative feature, you can now collaborate with other editor on any story using Google Docs.
You cannot directly publish content using chrome extension. You still have to navigate back to dashboard to publish the story. WordPress.com for Google Docs Chrome Extension is now available to any website hosted on WordPress.com. It is also accessible to any independent website running WordPress.com and Jetpack-connected WordPress site.
Read more on The Tech Portal: WordPress.com finally gives us the power of collaborative editing via Google Docs extension
The integration also comes with a sidebar where you can keep track of all authorized sites and collaborators working. Once you save a draft, the add-on will generate a preview link where you can check out how the content will appear when published.
Source code on GitHub