GitLab

Everything related to creating a WAV file from an AudioBuffer is moved
from audit-util.js to a new file.

Every test depending on these utilities now needs to import this
script.

No functional changes.

Bug: 776110
Change-Id: Ib3d4ddd4bc3fe5e743dd5c3f7b758b6f57940e7d
Reviewed-on: https://chromium-review.googlesource.com/726947Reviewed-by: Hongchan Choi <hongchan@chromium.org>
Commit-Queue: Raymond Toy <rtoy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512954}