The Typeface.create(Typeface, int) API can be used to create a new typeface derived from an existing typeface. The implementation would however create a new Typeface instance on every call, creating unnecessary garbage in text-heavy applications. This changelist adds a small cache of derived typefaces to avoid allocations whenever possible. Change-Id: Ib7290b3183e372aae12cf66033690e15cd4d0691