For quick and easy aecdump verifiation storing data as text speeds up the issue tracking process, since anyone can simply view values like mic volume. BUG=4609 TESTED=verified unpacking an aecdump with flag --txt stores that data in text files R=kwiberg@webrtc.org Review URL: https://webrtc-codereview.appspot.com/50849004 Cr-Commit-Position: refs/heads/master@{#9142}