Override isWindowPrivate() for gBrowser.setIcon() + use base64 representation for icon of image document
Note: doesn't work in SeaMonkey
(workaround for #56)
Disable thumbnails capturing from private tabs
(closes #58)
Always override PrivateBrowsingUtils.isWindowPrivate():
we now use this patch for tabs icons
(related to #56)
Improve performance: use original PrivateBrowsingUtils.isWindowPrivate() for internal calls
Improve performance: use window.content to get private state of selected tab
Because this is window.gBrowser.selectedTab.linkedBrowser.contentWindow