Revert of scheduler: Add a base directory

Revert of scheduler: Add a base directory (patchset #4 id:60001 of https://codereview.chromium.org/1374653003/ )

Reason for revert:
Change causes compile failure:
http://build.chromium.org/p/chromium.linux/builders/Linux%20GN%20Clobber/builds/6135

Original issue's description:
> scheduler: Add a base directory
>
> This patch moves the more fundamental scheduling primitives (e.g.,
> TaskQueueManager) to a separate base/ directory. This makes the layered
> architecture of the scheduler more obvious and reduces the likelihood of
> accidentally introducing layering violations.
>
> With this refactoring, the overall dependencies are:
>
>        +------+
>        | base |
>        +------+
>            ^
>            |
>        +-------+     +------+
>        | child |<----| test |
>        +-------+     +------+
>           ^ ^          ^ ^
>           | |          | |
>           | '----------|-|---.
>           | .----------' '-. |
>           | |              | |
>       +----------+      +-------+
>       | renderer |      | ppapi |
>       +----------+      +-------+
>
> Committed: https://crrev.com/516bee16e9437521cdd20a78d683f9dbaf35df3e
> Cr-Commit-Position: refs/heads/master@{#351109}

TBR=jochen@chromium.org,alexclarke@chromium.org,skyostil@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/8416901cc7796ee6892942bcda40b83f0e5a1bb4
Cr-Commit-Position: refs/heads/master@{#351171}

[pavely, 2015-09-28 22:10:53]

Created Revert of scheduler: Add a base directory

[commit-bot: I haz the power, 2015-09-28 22:13:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1370343002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1370343002/1

[commit-bot: I haz the power, 2015-09-28 22:17:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-28 22:17:50]

Patchset 1 (id:??) landed as
https://crrev.com/8416901cc7796ee6892942bcda40b83f0e5a1bb4
Cr-Commit-Position: refs/heads/master@{#351171}