Revert of Large wallpaper decoding in utility process

Revert of Large wallpaper decoding in utility process (patchset #5 id:190001 of https://codereview.chromium.org/482163002/)

Reason for revert:
Speculative revert for unit_tests failures:

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/31845/steps/unit_tests/logs/DecodeImageSizeLimit

Original issue's description:
> Handle large wallpaper decoding in utility process:
> Images over 32M pixels exceed IPC message limit size.  In ChromeContentUtilityClient::DecodeImage(), cut image dimensions in half to minimize quality loss and allow decoded image to be returned via IPC message.
>
> BUG=366825
> TEST=ChromeContentUtilityClientTest.DecodeImageSizeLimit; Set ChromeOS wallpaper using JPGs attached to bug
>
> Committed: https://crrev.com/d9d0e601c4c45ec8f2fb1d148e68458d9baa4e24
> Cr-Commit-Position: refs/heads/master@{#296407}

TBR=dcheng@chromium.org,bshe@chromium.org,skuhne@chromium.org,sky@chromium.org,tsepez@chromium.org,yoz@chromium.org,glevin@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=366825
Committed: https://crrev.com/4ef72fa49c0650d716205c0686ee0268070281ff
Cr-Commit-Position: refs/heads/master@{#296457}

[jiayl, 2014-09-24 17:52:49]

Created Revert of Large wallpaper decoding in utility process

[commit-bot: I haz the power, 2014-09-24 17:53:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/600913002/1

[commit-bot: I haz the power, 2014-09-24 17:54:58]

Committed patchset #1 (id:1) as ca7cd59737f4ba85af448d7ffd28bbcfc2281eb8

[commit-bot: I haz the power, 2014-09-24 17:55:49]

Patchset 1 (id:??) landed as
https://crrev.com/4ef72fa49c0650d716205c0686ee0268070281ff
Cr-Commit-Position: refs/heads/master@{#296457}