On mobile devices, there is typically only a single audio device. We may
open it once and reuse it to stream audio buffers from multiple sources.
This assumption also applies to the context since OpenAL contextes are
process-wide. A shared global pointer is reusable across multiple
OpenAL sources.
This CL also removes the Device and Context types and the unexpected
garbage collection issue introduced by Context's finalizer.
Fixesgolang/go#10636
Change-Id: I82e6e6e6a1500ba91d66a7848cf37d1a5e01af9b
Reviewed-on: https://go-review.googlesource.com/9782
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
a8aa7bbd72