Revert of Start calling show/hide onStart/onStop in DocumentActivity

Revert of Start calling show/hide onStart/onStop in DocumentActivity (patchset #1 id:1 of https://codereview.chromium.org/1455343002/ )

Reason for revert:
BUG=559197
This was causing an early tab.show call which made the test think the activity is in the foreground.

Reverting my CL for now. Will have to figure out a proper way to hide/show to reland.

Original issue's description:
> Start calling show/hide onStart/onStop in DocumentActivity
>
> This logic in documents diverge from CHromeActivity behavior for
> archaic reasons (crbug.com/451672). Making documents show/hide
> in the same time as all other ChromeActivities with this change.
> Verified that the previous bug that caused the bheavior divergence
> no longer exists after this CL.
>
> BUG=546182
>
> Committed: https://crrev.com/e548d4580bbd915716a855f9195b6f5f2d63d2a1
> Cr-Commit-Position: refs/heads/master@{#360581}

TBR=dfalcantara@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=546182
Committed: https://crrev.com/bc113d52b7f5fbf39123f4b43ea779ee2dd587c3
Cr-Commit-Position: refs/heads/master@{#361223}

[Yusuf, 2015-11-24 00:05:01]

Created Revert of Start calling show/hide onStart/onStop in DocumentActivity

[commit-bot: I haz the power, 2015-11-24 00:09:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1464313003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1464313003/1

[commit-bot: I haz the power, 2015-11-24 00:11:35]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-24 00:12:25]

Patchset 1 (id:??) landed as
https://crrev.com/bc113d52b7f5fbf39123f4b43ea779ee2dd587c3
Cr-Commit-Position: refs/heads/master@{#361223}