IIRC, Chrome was using the FileSystem API which was supported only in Chrome - hence the partial support for offline functionality in Google docs..Only recently have the specs behind Persistent Storage API and Service workers have matured. I would love to see Google docs to make use of these APIs to make the functionality available across browsers.
Also, PNacl -> Web Assembly which Google has supported.
Of course Android OSes are going to ship with Chrome as a default browser - at least you have the choice of installing a different browser if you want to. Unlike Apple, where all browsers are forced to use the same JS engine provided by Apple.
Google has been pushing web standards for a long time now - instead of platform specific APIs and saying that the internet is going to be only accessible from Chrome is stretching it quite a bit..