Revert of Fix accessibility issues in AudioPlayer and VideoPlayer.

Revert of Fix accessibility issues in AudioPlayer and VideoPlayer. (patchset #4 id:60001 of https://codereview.chromium.org/1415953006/ )

Reason for revert:
We decided to punt redesign of audio player to M49.

Original issue's description:
> Fix accessibility issues in AudioPlayer and VideoPlayer.
>
> This CL includes:
> - Make each control focusable.
> - Implement blue outline for focused-by-keyboard buttons.
> - Add aria-label for buttons and sliders.
> - Extracted common behaviors of icon buttons as files-icon-button.
>
> BUG=551267, 533604
> TEST=manually tested using ChromeVox.
>
> Committed: https://crrev.com/11e80965386a3488f6ef9d4bb94722a4f5ba83f9
> Cr-Commit-Position: refs/heads/master@{#359041}

TBR=yawano@chromium.org,mtomasz@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=551267, 533604
Committed: https://crrev.com/b80b21af601044b3322a8012e8df3707b9e32b27
Cr-Commit-Position: refs/heads/master@{#359281}

[fukino, 2015-11-12 08:15:50]

Created Revert of Fix accessibility issues in AudioPlayer and VideoPlayer.

[commit-bot: I haz the power, 2015-11-12 08:16:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1441603002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1441603002/1

[commit-bot: I haz the power, 2015-11-12 08:17:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-12 20:05:47]

Patchset 1 (id:??) landed as
https://crrev.com/b80b21af601044b3322a8012e8df3707b9e32b27
Cr-Commit-Position: refs/heads/master@{#359281}