Browser extensions support is one of the biggest reasons Firefox has become so popular and is also the most requested feature by users of the Google Chrome browser. Thus it is not surprising the search giant would want to add support for them and in fact they have already laid out a plan for the feature.
Particularly Google claims user created extensions should solve three problems in Chrome: the addition of features that have specific or limited appeal, it would make life easier for users coming from other browsers that support extensions "they can't live without," and it will allow partners who want to create their own Chrome bundle to add specific features.
The company is not offering a timeline for the extension system but are making it a priority, to the point of specifically mentioning a bunch of popular Firefox extensions they would like to support: Stumble Upon, Delicious Toolbar, FlashGot, ForecastFox, the Skype extension and even AdBlock - despite of the fact Google relies heavily on advertising to generate the bulk of their revenues, they also seem to want this option to be available in their browser.