This allows it to be reused with Android AudioRecords created outside
WebRtcAudioRecord. WebRtcAudioEffects provides useful methods for enabling
hardware effects (such as echo cancellation) only on appropriate devices. It
also allows some control of these effects through WebRtcAudioUtils.
BUG=webrtc:7448
Review-Url: https://codereview.webrtc.org/2786603004
Cr-Commit-Position: refs/heads/master@{#18053}