Revert of Refactor the avatar button/icon class

Revert of Refactor the avatar button/icon class (patchset #14 id:320001 of https://codereview.chromium.org/1009403002/)

Reason for revert:
Very likely has caused the latest flakiness of
BrowserNonClientFrameViewAshTest.AvatarDisplayOnTeleportedWindow
and
BrowserNonClientFrameViewAshTest.AvatarMenuButtonHitTestOnChromeOS

on
ChromeOS dbg:

https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/2069

Original issue's description:
> Refactor the avatar button/icon class.
> Such that they are based on the same base class.
>
> BUG=452524
>
> Committed: https://crrev.com/56078ce434955a67159b59303f6691adb55d7ca1
> Cr-Commit-Position: refs/heads/master@{#329249}

TBR=noms@chromium.org,msw@chromium.org,yiyaoliu@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=452524
Committed: https://crrev.com/73d41c0f28f554afca1771020363ca0daee24195
Cr-Commit-Position: refs/heads/master@{#329394}

[pneubeck (no reviews), 2015-05-12 12:28:08]

Created Revert of Refactor the avatar button/icon class

[commit-bot: I haz the power, 2015-05-12 12:28:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139943002/1

[commit-bot: I haz the power, 2015-05-12 12:29:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-12 12:29:57]

Patchset 1 (id:??) landed as
https://crrev.com/73d41c0f28f554afca1771020363ca0daee24195
Cr-Commit-Position: refs/heads/master@{#329394}