Revert of BrowserWindowCocoa::Show should activate the window

Revert of BrowserWindowCocoa::Show should activate the window (patchset #1 id:1 of https://codereview.chromium.org/1166643003/ )

Reason for revert:
Caused regression: http://crbug.com/500038, and http://crbug.com/496786

Original issue's description:
> BrowserWindowCocoa::Show should activate the window
>
> When a new tab/window is opened on Mac, the window is currently brought
> to the front relative to other Chrome windows, but not relative to other
> apps. This often goes unnoticed, since Chrome is often already the
> active app, but it's particularly noticeable when clicking on a push
> notification opens a new tab/window, as this window will remain
> underneath other apps if Chrome wasn't already in the foreground.
>
> This patch makes Show always Activate the window as well.
>
> BUG=470830
> TEST=manual, follow steps in https://crbug.com/470830
>
> Committed: https://crrev.com/b13b6d7b2c7ad67c1b1937897fe3c26527eeb943
> Cr-Commit-Position: refs/heads/master@{#332615}

R=avi@chromium.org,johnme@chromium.org
BUG=470830
Committed: https://crrev.com/bfacce0691d0ffe7551e2b35a816c1503a9d489a
Cr-Commit-Position: refs/heads/master@{#349884}

[Andre, 2015-09-18 21:53:40]

Created Revert of BrowserWindowCocoa::Show should activate the window

[Andre, 2015-09-20 00:44:04]

PTAL

[Andre, 2015-09-20 00:44:13]

The CQ bit was checked by andresantoso@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-20 00:44:19]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1359483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1359483002/1

[commit-bot: I haz the power, 2015-09-20 01:08:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-20 01:08:44]

Dry run: This issue passed the CQ dry run.

[Avi (use Gerrit), 2015-09-20 16:03:30]

lgtm

[Avi (use Gerrit), 2015-09-20 16:03:36]

The CQ bit was checked by avi@chromium.org

[commit-bot: I haz the power, 2015-09-20 16:03:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1359483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1359483002/1

[commit-bot: I haz the power, 2015-09-20 22:38:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-20 22:38:52]

Patchset 1 (id:??) landed as
https://crrev.com/bfacce0691d0ffe7551e2b35a816c1503a9d489a
Cr-Commit-Position: refs/heads/master@{#349884}