Use audio/mpeg instead of audio/mp3 for .mp3 files

audio/mpeg is used instead of audio/mp3 in safari and firefox for .mp3
files, as defined in this rfc: https://tools.ietf.org/html/rfc3003

Bug: 227004
Change-Id: Ie3e244f5c2ea4550237c6856437dc4aa575bd7fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1989133
Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Mason Freed <masonfreed@chromium.org>
Commit-Queue: Joey Arhar <jarhar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730910}
3 files changed