Assume that Android >= 8 always have echo cancellation, even if AcousticEchoCanceller.isAvailable() returns false, and assume that OpenSLES works with echo canceller by default. Indeed, we find more and more devices that have hardware echo canceller but do not report it via AcousticEchoCanceller.isAvailable(). If it is not true for some devices, a specific line should be added in devices.c for this device.