The setShelfEnabled()
function of the downloads
API enables or disables the gray shelf at the bottom of every window associated with the current browser profile. The shelf will be disabled as long as at least one extension has disabled it.
If you try to enable the shelf when at least one other extension has already disabled it, the call will fail and runtime.lastError
will be set with an appropriate error message.
Note: To use this function in your extension you must ask for the "downloads.shelf"
manifest permission, as well as the "downloads"
permission.