On compilers that don't support enum class, we define it as a class and define our own constructors. These override the default constructors, so
no longer works. We need a default constructor with zero arguments that does nothing.
Created attachment 652067 [details] [diff] [review]
Green try: https://tbpl.mozilla.org/?tree=Try&rev=8d6b61bf89ac
Backed out for Android builds failures:
Sorry, was looking at the wrong push. Relanded: