Revert of mac: Tentative fix for Yosemite open file crash.

Revert of mac: Tentative fix for Yosemite open file crash. (patchset #5 id:70001 of https://codereview.chromium.org/941453002/)

Reason for revert:
Speculative revert. This CL might be responsible for inverted text in omnibox.

https://code.google.com/p/chromium/issues/detail?id=479097

Original issue's description:
> mac: Tentative fix for Yosemite open file crash.
>
> There's a bug in AppKit that causes Chrome to crash when users attempt to save
> or open a file. The code path that causes the crash is only hit by applications
> linked against OSX 10.7 SDK (or earlier). This CL registers a default value for
> the preference NSViewKeepLayersAround, which prevents this code path from being
> hit. The functional implications of changing the preference
> NSViewKeepLayersAround are minimal.
>
> BUG=428977
>
> Committed: https://crrev.com/192b9d9cfe388a6cfb76b9aea56070da1d878a81
> Cr-Commit-Position: refs/heads/master@{#316968}

TBR=andresantoso@chromium.org,avi@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=428977
Committed: https://crrev.com/e771ecf956c01834866e5c1caaad97977ca6fda4
Cr-Commit-Position: refs/heads/master@{#326585}

[erikchen, 2015-04-23 18:23:01]

Created Revert of mac: Tentative fix for Yosemite open file crash.

[commit-bot: I haz the power, 2015-04-23 18:25:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1104733002/1

[commit-bot: I haz the power, 2015-04-23 18:27:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-23 18:28:54]

Patchset 1 (id:??) landed as
https://crrev.com/e771ecf956c01834866e5c1caaad97977ca6fda4
Cr-Commit-Position: refs/heads/master@{#326585}

[Andre, 2015-04-24 00:11:12]

LGTM