non-const reference parameters in new and older code

https://google.github.io/styleguide/cppguide.html#Reference_Arguments has a simple rule to determine when reference parameters are permitted: "Within function parameter lists all references must be const." This is consistent with Mozilla's previous coding style: "Use pointers, instead of references

precedence of Mozilla, Google, and clang-format styles for C++ code

Near the top of https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style there is > New code should try to conform to these standards, so it is as > easy to maintain as existing code. [...] > > This article is particularly for those new to the Mozilla > codebase [...]" Before