Extensions Quality Guidelines
An extension must have a single purpose that is narrow and easy-to-understand. Do not create an extension that requires users to accept bundles of unrelated functionality, such as an email notifier and a news headline aggregator, or downloads a local executable. If two pieces of functionality are clearly separate, they should be put into two different extensions, and users should have the ability to install and uninstall them separately. For example, functionality that displays product ratings and reviews, but also injects ads into web pages, should not be bundled into a single extension. Similarly, toolbars that provide a broad array of functionality or entry points into services are better delivered as separate extensions, so that users can select the services they want. Please see this FAQ for more information.
Starting with Chrome Release 36, extensions that change Chrome settings on Windows must do so via the Settings Override API.