Does just calling CreateAboutBlankContentViewer() not do the right thing?
Created attachment 600103 [details] [diff] [review] attempt #1 I'm not confident this patch is suitable to land, but it's a quick hack to test whether this approach would work. It doesn't seem to work (the new tab page stays loaded and the JS doesn't run), but I don't really know why.
Workaround: Change the new tab page as described here https://support.mozilla.org/en-US/kb/new-tab-page-show-hide-and-customize-top-sites#w_how-do-i-turn-the-new-tab-page-off Setting it to e.g. about:blank makes the bookmarklets work again. This is obviously only viable if you think it's acceptable to get a blank page when opening a new tab.
Mass-move to Firefox::New Tab Page. Filter on new-tab-page-component.
Now that browser.newtab.url has been disabled, imo, this is a great annoiance.
You should probably just install https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/ for now like I just did, pending bug 776477 getting fixed.
Thanks a lot Boris, this add-on is what I want, perfect :-)