Revert of Adds shadow assets to wm

Revert of Adds shadow assets to wm (patchset #1 id:1 of https://codereview.chromium.org/1471693004/ )

Reason for revert:
Reverting as I'm going to use resources directly from ui.

Original issue's description:
> Adds shadow assets to wm
>
> They are not used yet, but will be soon.
>
> BUG=548424
> TEST=none
> R=ben@chromium.org
> TBR=ben@chromium.org
>
> Committed: https://crrev.com/601fa0ceded73ccb158db9d9c223db1ea4c2c8b0
> Cr-Commit-Position: refs/heads/master@{#361234}

TBR=ben@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=548424
Committed: https://crrev.com/706cde61f17e1f898e80969023687465371cb0d3
Cr-Commit-Position: refs/heads/master@{#361487}

[sky, 2015-11-24 23:29:53]

Created Revert of Adds shadow assets to wm

[commit-bot: I haz the power, 2015-11-24 23:35:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1476693002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1476693002/1

[commit-bot: I haz the power, 2015-11-24 23:38:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-24 23:38:59]

Patchset 1 (id:??) landed as
https://crrev.com/706cde61f17e1f898e80969023687465371cb0d3
Cr-Commit-Position: refs/heads/master@{#361487}