Added `mach uniffi generate` which executes `uniffi-bindgen-gecko-js` to
generate UniFFI bindings. It's unfortunate that we need to check these
files in, but I couldn't figure out a way to auto-generate them as part
of the build process.
Adding `#include "nsIContent.h"` to dom/base/nsINodeList.h. I think
that should have been present before, but things built okay because of
the way things got combined in the uniffied .cpp files. Adding these new
webIDL files bumped `NodeListBinding.cpp` to a new uniffied .cpp file
which caused the build to fail.
Differential Revision: https://phabricator.services.mozilla.com/D144468
86a582c07a