Revert of Task Manager Should remember the most recently enabled columns.

Revert of Task Manager Should remember the most recently enabled columns. (patchset #6 id:100001 of https://codereview.chromium.org/1320563002/ )

Reason for revert:
NewTaskManagerViewTest.ColumnsSettingsAreRestored crashes on Linux ChromiumOS Tests (dbg)(1).

https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/6380/steps/browser_tests/logs/NewTaskManagerViewTest.ColumnsSettingsAreRestored

Original issue's description:
> Task Manager Should remember the most recently enabled columns.
>
> This CL:
> 1- Makes adding and removing columns to the task manager a lot easier
> and cleaner.
> 2- Stores/retrieves the columns visibility to/from the local state
> prefs.
> 3- Stores/retrieves the sorted column and the sort order.
>
> R=thestig@chromium.org
> BUG=452521
> TEST=browser_tests --gtest_filter=NewTaskManagerViewTest.*
>
> Committed: https://crrev.com/4e16add803fbb0ed18413496d3fb4424fa4957c6
> Cr-Commit-Position: refs/heads/master@{#346524}

TBR=thestig@chromium.org,afakhry@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=452521
Committed: https://crrev.com/632a48fe73baa3f24e8273ecd8fa549764edc57a
Cr-Commit-Position: refs/heads/master@{#346556}

[horo, 2015-09-01 02:09:56]

Created Revert of Task Manager Should remember the most recently enabled
columns.

[commit-bot: I haz the power, 2015-09-01 02:10:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1323853005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1323853005/1

[commit-bot: I haz the power, 2015-09-01 02:10:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-01 02:11:41]

Patchset 1 (id:??) landed as
https://crrev.com/632a48fe73baa3f24e8273ecd8fa549764edc57a
Cr-Commit-Position: refs/heads/master@{#346556}