The TickTimer is incremented on each call to GetAudioInternal(). Other than that, the new object is not used yet. Also adding a unit test in NetEqImplTest to verify that the tick timer is incremented in the call to NetEq::GetAudio. BUG=webrtc:5608 Review URL: https://codereview.webrtc.org/1903153005 Cr-Commit-Position: refs/heads/master@{#12493}