Shared components used by Firefox and other Mozilla software, including handling of Web content; Gecko, HTML, CSS, layout, DOM, scripts, images, networking, etc. Issues with web page layout probably go here, while Firefox user interface issues belong in the Firefox product. (More info)
This is similar to bug 1062275, but
since there are a lot more GetCurrentDoc callers, this work should be done in
several patches, or even better in several bugs in which case this bug could be just a meta bug.