This CL contains an Android-specific Manager implementation. On Android, we create a new ALooper for each Manager instance and all CGO calls are proxified to an OS-thread-locked goroutine. Change-Id: I33272cd4369d0b7850f97e840fe4bbe5aee78ec0 Reviewed-on: https://go-review.googlesource.com/8249 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>