I have a patch which reduces sizeof(nsEditor) from 296 to 280 on 64-bit platforms.
Created attachment 617780 [details] [diff] [review] Patch (v1) http://tbpl.mozilla.org/?tree=Try&rev=4f2154cdaebf
How many nsEditor objects are we likely to have live at once?
Try run for 4f2154cdaebf is complete. Detailed breakdown of the results available here: https://tbpl.mozilla.org/?tree=Try&rev=4f2154cdaebf Results (out of 73 total builds): success: 56 warnings: 7 failure: 10 Builds (or logs if builds failed) available at: http://firstname.lastname@example.org
(In reply to Nicholas Nethercote [:njn] from comment #2) > How many nsEditor objects are we likely to have live at once? Currently, one per textarea element on the page, one per <input type=text> if you've interacted with them (by focusing/typing/etc) or if the page script does some special things (because the nsEditor for those are initialized lazily), one per any text box in XUL documents, and one per HTML document which has an editable section.
And backed out, since we treat warnings as errors!