* fix: don't append Shift modifier text twice to accelerators
* style: use the new way of creating patches
* test: add menu item accelerator display tests
* fix: allocate accelerator on the stack
* fix: adjust tests to match expected behavior on mac
In the GN build, libchromiumcontent is no longer a distinct library, but
merely a container for a set of scripts and patches. Maintaining those
patches in a separate repository is tedious and error-prone, so merge
them into the main repo.
Once this is merged and GN is the default way to build Electron, the
libchromiumcontent repository can be archived.
