GitLab

 * Make it so the old command-line arg to set a fixed output sample rate
   works.
 * Avoid NaN in postprocessor volume calculation.

Bug: internal b/74089224
Change-Id: Ic9534d16e8eff5e24faf3cac8b41e8aa63c3397a
Reviewed-on: https://chromium-review.googlesource.com/960966Reviewed-by: Stephen Lanham <slan@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542975}