Currently the "browser_action" is implemented, along with these
APIs:
* chrome.extension.getURL
* chrome.extension.inIncognitoContext
* chrome.extension.isAllowedIncognitoAccess
* chrome.extension.isAllowedFileSchemeAccess
* chrome.extension.setUpdateUrlData
* chrome.history.addUrl
* chrome.history.deleteAll
* chrome.history.deleteUrl
* chrome.tabs.create
* chrome.tabs.duplicate
* chrome.tabs.getCurrent
* chrome.tabs.query
* chrome.tabs.remove