Not too surprising. Swift is too tied to Apple and it's not really clear what the benefit would be relative to a subset of C++ written with contemporary memory safety practices. It's a battle tested choice and pretty much every browser actually in use is written in C++.
> a subset of C++ written with contemporary memory safety practices What is this mythical subset of C++? Does it include use of contemporary STL features like string_view? (Don’t get me wrong — modern STL is considerably improved, but it’s not even close to being memory-safe.)
class FontFeatureValuesMapIterationSource final
: public PairSyncIterable::IterationSource {
public:
FontFeatureValuesMapIterationSource(const CSSFontFeatureValuesMap& map,
const FontFeatureAliases* aliases)
: map_(map), aliases_(aliases), iterator_(aliases->begin()) {}