For me the following reported issue answered my question: Issue 158004: chrome.permissions.request support for user-supplied URL.
To make it clear: It is not possible to request a subset of the permissions defined in optional_permissions
. If you define http://*/*
then you need to request exactly this string! A subset like http://example.org/*
wont work!
Here is a quote from a comment in the issue description which makes that clear: "There's no wildcard handling, just plain string comparison between the URLPatterns"
The Issue has been fixed in Revision 182287
The only thing left is to cross your fingers that this fix gets included in a upcomming chrome release soon. We'll have to use the bloody Access your data on all websites
permission in the meanwhile.